Multiple Application for Novel and Advanced Materials

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Materials materials	3.4	5.2	2008	13.9 Days	CHF 2600
Coatings coatings	3.4	4.7	2011	13.8 Days	CHF 2600
Polymers polymers	5.0	6.6	2009	13.7 Days	CHF 2700
Fibers fibers	3.9	7.0	2013	24.1 Days	CHF 2000

13 pages, 4885 KiB

Open AccessArticle

Anisotropic Piezoelectric Properties of Porous (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ Ceramics with Oriented Pores through TBA-Based Freeze-Casting Method

by Siyu Ge, Junzhan Zhang, Ying Zhang, Peng Shi, Honghui Wang, Shangyi Liu, Zhifeng Tian and Zongmo Shi

Materials 2022, 15(11), 3820; https://doi.org/10.3390/ma15113820 - 27 May 2022

Cited by 3 | Viewed by 1732

Abstract

Porous (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ (BCZT) piezoelectric ceramics with an oriented directional hole structure were prepared by using the tertbutyl alcohol (TBA)-based freeze-casting method. The influences of sintering temperatures on the microstructure and piezoelectric properties of porous [...] Read more.

Porous (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ (BCZT) piezoelectric ceramics with an oriented directional hole structure were prepared by using the tertbutyl alcohol (TBA)-based freeze-casting method. The influences of sintering temperatures on the microstructure and piezoelectric properties of porous BCZT ceramics were investigated both perpendicular and parallel to the freezing direction. With the increase in sintering temperatures and the porosities decreased from 58% to 42%, the compressive strength increased from 14.0 MPa to 25.0 MPa. In addition, the d₃₃ value of 407 pC/N for the sample sintered at 1400 °C was obtained parallel to the freezing direction, which was 1.40 times that of the other direction. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 9397 KiB

Open AccessArticle

Preparation of the Flexible Green Body of YAG Ceramic Fiber by Melt Spinning

by Hongmei Liu, Junjie Tian, Gangwei Pan, Yongjin Xie and Qing Yao

Polymers 2022, 14(10), 2096; https://doi.org/10.3390/polym14102096 - 20 May 2022

Cited by 2 | Viewed by 1752

Abstract

YAG ceramic fiber, with its high thermal conductivity and easy to achieve limit size, provides design flexibility as a laser gain medium. Its mainstream forming method was mainly high-pressure extrusion, but there were disadvantages, such as lack of flexibility. In this work, the [...] Read more.

YAG ceramic fiber, with its high thermal conductivity and easy to achieve limit size, provides design flexibility as a laser gain medium. Its mainstream forming method was mainly high-pressure extrusion, but there were disadvantages, such as lack of flexibility. In this work, the flexible green body of YAG ceramic fiber was prepared by melt spinning. The melting characteristics of TPU with four different Shore hardnesses were systematically investigated. The microstructure, element homogeneity of the surface and fracture SEM images of the prepared ceramic fiber were also analyzed in detail. The optimized process parameters of YAG ceramic fiber preparation were as follows: the melting temperature was 220 °C, the screw feed rate of the double-cone screw extruder was F = 15.0 mm/min and the TPU-95A# was used. The ceramic fiber with the mass ratio of TPU-95A# to ceramic powder = 4:6 had the best microstructure quality. It had good flexibility and could be knotted with a bending radius of about 2.5 mm, and the tensile strength reached approximately 20 MPa. These results are crucial for advancing YAG ceramic fiber applications. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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29 pages, 5193 KiB

Open AccessArticle

Corrosion Enhancement for FGM Coolant Pipes Subjected to High-Temperature and Hydrostatic Pressure

by Kai-Chien Lo and Hsin-Yi Lai

Coatings 2022, 12(5), 666; https://doi.org/10.3390/coatings12050666 - 13 May 2022

Cited by 3 | Viewed by 1729

Abstract

The objective of this paper is to enhance the corrosion resistance of coolant pipes in high temperature and lateral hydrostatic pressure in critical engineering environment, especially for circular coolant pipes under hydrostatic pressure of LBE (lead-bismuth eutectic) applications in nuclear power plants. The [...] Read more.

The objective of this paper is to enhance the corrosion resistance of coolant pipes in high temperature and lateral hydrostatic pressure in critical engineering environment, especially for circular coolant pipes under hydrostatic pressure of LBE (lead-bismuth eutectic) applications in nuclear power plants. The resistance against corrosion caused by LBE liquid is mainly formed by Fe-12Cr-2Si solid solutions coatings on the pipe. The silicon concentration in Fe-12Cr-2Si can interact with LBE as an effective oxidized compound such as SiO₂ and Fe₂SiO₄ when the silicon concentration is higher than 1.25 wt.%. The oxide film formed on the coating can resist the LBE corroding in the Fe-12Cr-2Si structure. The primary material of a constructing coolant pipe is T91 ferritic-martensitic alloys, and the surface anti-corrosion coating is Fe-12Cr-2Si solid solution. With a high strength structure, FGC (functionally graded composite material), ensures that the pipe resists the corrosion from LBE liquid. In this study, both the steady-state stress values and silicon concentration are evaluated at 700, 1000, and 1200 °C to know the fatigue problems. The research result indicates the FGM (functionally graded material) structure performs better in promoting the margin of safety on stress distribution and reserving the silicon concentration on the inner surface higher than 1.25 wt.% over 60 years as compared to the FGC structure with 34 μm thickness of Fe-12Cr-2Si coating in a high temperature environment. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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9 pages, 1088 KiB

Open AccessArticle

The Effect of Ligature Type on Lateral Tooth Movement during Orthodontic Treatment with Lingual Appliances—An In Vitro Study

by Elisabeth Reichardt, Steffen Decker, Michel Dalstra, Prasad Nalabothu, Markus Steineck, Leandro Fernandez and Carlalberta Verna

Materials 2022, 15(9), 3365; https://doi.org/10.3390/ma15093365 - 7 May 2022

Viewed by 2115

Abstract

(1) Background: One of the most challenging parts in lingual orthodontics is the control and correction of the tip of anterior teeth, due to the occlusal open vertical slot of the incisors in lingual systems. The presented experimental in-vitro study was performed to [...] Read more.

(1) Background: One of the most challenging parts in lingual orthodontics is the control and correction of the tip of anterior teeth, due to the occlusal open vertical slot of the incisors in lingual systems. The presented experimental in-vitro study was performed to determine the maximal tipping moment of the anterior teeth between two types of lingual brackets, the Incognito™ Appliance System (Incognito, TOP-Service, Bad Essen, Germany) and Tip-Bar™ system (Incognito, TOP-Service, Bad Essen, Germany). Furthermore, twelve different ligation methods and two different ligature materials were investigated. (2) Methods: The measurement was performed by assessing the stiffness and ultimate strength of the ligature in a uniaxial material testing machine (Instron, Norwood, MA, USA) using a 0.025 × 0.018 inch stainless steel wire. (3) The results showed that the highest precision for control tipping of anterior teeth was determined for the 0.010 inch Stainless Steel Tie (Pelz and Partner). Furthermore, the Tip-Bar™ brackets increased the maximal moment by 33.8% for elastic and steel ligatures. (4) Conclusions: The lateral tooth movement is highly dependent on the type of ligature and applied material during orthodontic treatment with lingual appliances. The use of 0.010 inch steel ligatures and the Tip-Bar™ bracket design results in better alignment in the anterior teeth segment. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 7750 KiB

Open AccessArticle

Mechanical Properties and Microstructural Evolution of TiNi-Based Intermetallic Alloy with Nb Addition

by Hsin-Feng Yang, Tao-Hsing Chen and Ying-Ying Syu

Materials 2022, 15(9), 3124; https://doi.org/10.3390/ma15093124 - 26 Apr 2022

Cited by 1 | Viewed by 1544

Abstract

TiNi intermetallic alloys were prepared with 2, 4 and 6 at.% niobium (Nb) addition. The mechanical properties and microstructures of the alloys were investigated under both static (1 × 10⁻¹ to 1 × 10⁻³ s⁻¹) and dynamic (4 × [...] Read more.

TiNi intermetallic alloys were prepared with 2, 4 and 6 at.% niobium (Nb) addition. The mechanical properties and microstructures of the alloys were investigated under both static (1 × 10⁻¹ to 1 × 10⁻³ s⁻¹) and dynamic (4 × 10³ to 6 × 10³ s⁻¹) loading conditions. The intermetallic alloy structures and surface morphologies of the alloys were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. In addition, the fracture morphologies were observed by optical microscopy (OM). It was shown that the addition of 2 to 4 at.% Nb increased the strength of the TiNi alloy. However, as the level of Nb addition was further increased to 6 at.%, a significant reduction in strength occurred. For a constant Nb addition, the plastic flow stress and strain rate sensitivity increased with increasing strain rate under both loading conditions (static and dynamic). The XRD and SEM results showed that the original surface morphologies were composed primarily of dendritic structures and fine β-Nb + TiNi eutectic systems. Moreover, the OM results showed that the alloys underwent a transition from a brittle fracture mode to a ductile fracture mode as the level of Nb addition increased. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 6940 KiB

Open AccessArticle

3D Natural Mesoporous Biosilica-Embedded Polysulfone Made Ultrafiltration Membranes for Application in Separation Technology

by Murali Krishna Paidi, Veerababu Polisetti, Krishnaiah Damarla, Puyam Sobhindro Singh, Subir Kumar Mandal and Paramita Ray

Polymers 2022, 14(9), 1750; https://doi.org/10.3390/polym14091750 - 26 Apr 2022

Cited by 7 | Viewed by 2638

Abstract

Diatoms are the most abundant photosynthetic microalgae found in all aquatic habitats. In the extant study, the spent biomass (after lipid extraction) of the centric marine diatom Thalassiosira lundiana CSIRCSMCRI 001 was subjected to acid digestion for the extraction of micro composite inorganic [...] Read more.

Diatoms are the most abundant photosynthetic microalgae found in all aquatic habitats. In the extant study, the spent biomass (after lipid extraction) of the centric marine diatom Thalassiosira lundiana CSIRCSMCRI 001 was subjected to acid digestion for the extraction of micro composite inorganic biosilica. Then, the resulting three-dimensional mesoporous biosilica material (diatomite) was used as a filler in polysulfone (PSF) membrane preparation by phase inversion. The fabricated PSF/diatomite composite membranes were characterized by SEM-EDX, TGA, and ATR-IR, and their performances were evaluated. The number of pores and pore size were increased on the membrane surface with increased diatomite in the composite membranes as compared to the control. The diatomite composite membranes had high hydrophilicity and thermal stability, lower surface roughness, and excellent water permeability. Membranes with high % diatomite, i.e., PSF/Dia_0.5, had a maximum water flux of 806.8 LMH (Liter/m²/h) at 20 psi operating pressure. High-diatomite content membranes also exhibited the highest rejection of BSA protein (98.5%) and rhodamine 6G (94.8%). Similarly, in biomedical rejection tests, the PSF/Dia_0.5 membrane exhibited a maximum rejection of ampicillin (75.84%) and neomycin (85.88%) at 20 Psi pressure. In conclusion, the mesoporous inorganic biosilica material was extracted from spent biomass of diatom and successfully used in filtration techniques. The results of this study could enhance the application of natural biogenic porous silica materials in wastewater treatment for water recycling. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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25 pages, 7334 KiB

Open AccessReview

A Review of In-Service Coating Health Monitoring Technologies: Towards “Smart” Neural-Like Networks for Condition-Based Preventive Maintenance

by Xavier Frias-Cacho, Mickaël Castro, Dang-Dan Nguyen, Anne-Marie Grolleau and Jean-Francois Feller

Coatings 2022, 12(5), 565; https://doi.org/10.3390/coatings12050565 - 21 Apr 2022

Viewed by 2905

Abstract

In line with the recent industrial trends of hyperconnectivity, 5G technology deployment, the Internet of Things (IoT) and Industry 4.0, the ultimate goal of corrosion prevention is the invention of smart coatings that are able to assess their own condition, predict the onset [...] Read more.

In line with the recent industrial trends of hyperconnectivity, 5G technology deployment, the Internet of Things (IoT) and Industry 4.0, the ultimate goal of corrosion prevention is the invention of smart coatings that are able to assess their own condition, predict the onset of corrosion and alert users just before it happens. It is of particular interest to tackle corrosion that occurs in non-accessible areas where human inspectors or handheld devices are useless. To accomplish this, a variety of technologies that are embedded or could potentially be embedded into the coatings are being developed to monitor coating condition, which are based, for instance, on the evolution of electrochemical or mechanical properties over time. For these technologies to be fully embedded into the coatings and work remotely, solutions are needed for connectivity and power supply. A paradigm shift from routine prescheduled maintenance to condition-based preventive maintenance could then become a reality. In this work, the technologies that enable the in-service monitoring of organic anticorrosion coatings were compiled. Soon, some of them could be integrated into the sensing elements of autonomous, connected neural-like networks that are capable of remotely assessing the condition of the anticorrosion protection of future infrastructures. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 4877 KiB

Open AccessArticle

Preparation of a Heterogeneous Catalyst CuO-Fe₂O₃/CTS-ATP and Degradation of Methylene Blue and Ciprofloxacin

by Ting Zhang, Wenhui Li, Qiyang Guo, Yi Wang and Chunlei Li

Coatings 2022, 12(5), 559; https://doi.org/10.3390/coatings12050559 - 20 Apr 2022

Cited by 4 | Viewed by 1902

Abstract

A heterogeneous particle catalyst (CuO-Fe₂O₃/CTS-ATP) was synthesized via injection molding and ultrasonic immersion method, which is fast and effective. The particle catalyst applied attapulgite (ATP) wrapped by chitosan (CTS) as support, which was loaded dual metal oxides CuO and [...] Read more.

A heterogeneous particle catalyst (CuO-Fe₂O₃/CTS-ATP) was synthesized via injection molding and ultrasonic immersion method, which is fast and effective. The particle catalyst applied attapulgite (ATP) wrapped by chitosan (CTS) as support, which was loaded dual metal oxides CuO and Fe₂O₃ as active components. After a series of characterizations of catalysts, it was found that CuO and Fe₂O₃ were successfully and evenly loaded on the surface of the CTS-ATP support. The catalyst was used to degrade methylene blue (MB) and ciprofloxacin (CIP), and the experimental results showed that the degradation ratios of MB and CIP can reach 99.29% and 86.2%, respectively, in the optimal conditions. The degradation mechanism of as-prepared catalyst was analyzed according to its synthesis process and ∙OH production, and the double-cycle catalytic mechanism was proposed. The intermediate products of MB and CIP degradation were also identified by HPLC-MS, and the possible degradation pathways were put forward. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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15 pages, 38081 KiB

Open AccessArticle

Dependable Performance of Thin Film Composite Nanofiltration Membrane Tailored by Capsaicin-Derived Self-Polymer

by Yuanyuan Tang, Lu Cao, Li Xu, Zhaoyu Wang, Qian Shi, Yingying Zhang and Liangmin Yu

Polymers 2022, 14(9), 1671; https://doi.org/10.3390/polym14091671 - 20 Apr 2022

Cited by 5 | Viewed by 1738

Abstract

To address trade-off and membrane-fouling challenges during the development of nanofiltration membranes, a thin-film composite membrane was prepared on the basis of interfacial polymerization regulated by adjusting the capsaicin-derived self-polymer poly N-(2-hydroxy-5-(methylthio) benzyl) acrylamide (PHMTBA) on the polysulfone substrate in this study. Through [...] Read more.

To address trade-off and membrane-fouling challenges during the development of nanofiltration membranes, a thin-film composite membrane was prepared on the basis of interfacial polymerization regulated by adjusting the capsaicin-derived self-polymer poly N-(2-hydroxy-5-(methylthio) benzyl) acrylamide (PHMTBA) on the polysulfone substrate in this study. Through the self-polymerization of the monomer HMTBA with varied contents, microwave-assisted technology was employed to develop a variety of PHMTBAs. It was discovered that PHMTBA is involved in the interfacial polymerization process. Piperazine and PHMTBA competed for the reaction with trimesoyl chloride, resulting in a flatter and looser membrane surface. The PHMTBA-modified membrane presented a typical double-layer structure: a thicker support layer and a thinner active layer. The addition of PHMTBA to membranes improved their hydrophilicity and negative charge density. As a result, the PHMTBA-modified membrane showed dependable separation performance (water flux of 159.5 L m⁻² h⁻¹ and rejection of 99.02% for Na₂SO₄) as well as enhanced anti-fouling properties (flux recovery ratio of more than 100% with bovine serum albumin-fouling and antibacterial efficiency of 93.7% against Escherichia coli). The performance of the prepared membranes was superior to that of most other modified TFC NF membranes previously reported in the literature. This work presents the application potential of capsaicin derivatives in water treatment and desalination processes. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 6484 KiB

Open AccessArticle

Enhancing Thermal Insulation of EPDM Ablators via Constructing Alternating Planar Architectures

by Hongjian Qu, Le Wang, Kun Hui, Cheng Bian, Hongyan Li, Yiwen Guan, Tao Luan and Ning Yan

Polymers 2022, 14(8), 1570; https://doi.org/10.3390/polym14081570 - 12 Apr 2022

Cited by 5 | Viewed by 2486

Abstract

Ethylene–propylene–diene monomer (EPDM) composites were usually enhanced with ablative additives to protect solid rocket motor (SRMs) casings. However, the poor thermal insulation caused by the high thermal conductive ablative fillers can lead to rocket motor failure. Herein, the novel EPDM composites containing alternating [...] Read more.

Ethylene–propylene–diene monomer (EPDM) composites were usually enhanced with ablative additives to protect solid rocket motor (SRMs) casings. However, the poor thermal insulation caused by the high thermal conductive ablative fillers can lead to rocket motor failure. Herein, the novel EPDM composites containing alternating layers of ablative EPDM (AM) and heat-insulated EPDM (HM) were prepared through layer-multiplying extrusion. Compared with conventional EPDM ablative material, the multilayer composites showed enhanced thermal insulation and mechanical properties that could be further improved by tuning the number of layers. The ablation and thermal insulation properties possessing in AM and HM layers could be combined by forced assembly during co-extrusion, and the alternating multilayer composite was capable of showing the effect of each component. In particular, compared with AM, the maximum back-face temperature with 40 alternating layers of AM/HM decreased from 96.2 °C to 75.6 °C during oxyacetylene test, while the good ablation properties were preserved in the AM component. This significant improvement was attributed to the planar orientation and densification of ablative additives, and the interruption of conductive pathways in the through-plane direction of AM/HM alternating laminate. The anisotropic EPDM composites featuring mechanical robustness, good ablative resistance and thermal insulation suggest considerable potential application in the aerospace industry. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 1309 KiB

Open AccessArticle

Synthesis and Properties Comparison of Low Dielectric Silicon Containing Polyimides

by Yuwei Chen, Yidong Liu and Yonggang Min

Materials 2022, 15(8), 2755; https://doi.org/10.3390/ma15082755 - 8 Apr 2022

Cited by 4 | Viewed by 1803

Abstract

Recent studies have shown that the introduction of silicon can effectively improve the dielectric properties of polyimide (PI), and the introduction of a silicon–oxygen bond can increase the flexibility of the PI molecular structure, which is conducive to reducing the moisture absorption rate [...] Read more.

Recent studies have shown that the introduction of silicon can effectively improve the dielectric properties of polyimide (PI), and the introduction of a silicon–oxygen bond can increase the flexibility of the PI molecular structure, which is conducive to reducing the moisture absorption rate of PI materials. In this experiment, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyl disiloxane (DSX) was mixed with 4,4′-diaminodiphenyl ether (ODA) in different proportions. A series of PI films containing silicon was obtained by random polymerization with pyromellitic dianhydride (PMDA), 3,3′,4,4′-diphenylketotetrahedral anhydride (BTDA) and biphenyl dianhydride (BPDA), and then tetrad copolymerization with three kinds of dianhydrides. At the same time, the PI structures were put into calculation software to obtain the simulated polarization results, and then the films were characterized by various properties. The results showed that the characterization results were consistent with that of simulation, and the best overall PI formula was when the ratio of diamines was 1:9 and mixed with PMDA. The performance data were as follows: the vitrification temperature was about 320 °C, T₅ was 551 °C, water absorption was 1.56%, dielectric constant (Dk) was 2.35, dielectric loss (Df) was 0.007, tensile strength was 70 MPa and elongation at break was 10.2%. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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15 pages, 5491 KiB

Open AccessArticle

An Eco-Friendly Polymer Composite Fertilizer for Soil Fixation, Slope Stability, and Erosion Control

by Tao Li, Fengli Dai, Yufeng He, Daqian Xu and Rongmin Wang

Polymers 2022, 14(7), 1461; https://doi.org/10.3390/polym14071461 - 3 Apr 2022

Cited by 4 | Viewed by 2726

Abstract

In the Loess Plateau region, the poor structure and properties of loess slopes will cause many types of geological disasters such as landslides, mudflow, land collapse, soil erosion, and ground cracking. In this paper, an eco-friendly polymer composite fertilizer (PCF) based on corn [...] Read more.

In the Loess Plateau region, the poor structure and properties of loess slopes will cause many types of geological disasters such as landslides, mudflow, land collapse, soil erosion, and ground cracking. In this paper, an eco-friendly polymer composite fertilizer (PCF) based on corn straw wastes (CS) and geopolymer synthesized from loess was studied. The characterization by FT-IR of the PCF confirmed that graft copolymer is formed, while morphological analysis by scanning electron microscopy and energy dispersive spectroscopy showed that geopolymer and urea were embedded in the polymer porous network. The effects of PCF contents on the compressive strength of loess were investigated. The PCF was characterized in terms of surface curing test, temperature and freeze-thaw aging property, water and wind erosion resistance, and remediation soil acidity and alkalinity property, which indicates that PCF can improve loess slope fixation and stability by physical and chemical effects. Moreover, the loess slope planting experiment showed that PCF can significantly increase the germination rate of vegetation from 31% to 68% and promote the survival rate of slope vegetation from 45.2% to 67.7% to enhance biological protection for loess slopes. The PCF meets the demands of building and roadbed slope protection and water-soil conservation in arid and semi-arid regions, which opens a new application field for multifunctional polymer composite fertilizers with low cost and environmental remediation. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 3592 KiB

Open AccessArticle

Preparation, Characterization, and Surface Modification of Cellulose Nanocrystal from Lignocellulosic Biomass for Immobilized Lipase

by Elvi Restiawaty, Neng Tresna Umi Culsum, Norikazu Nishiyama and Yogi Wibisono Budhi

Fibers 2022, 10(4), 33; https://doi.org/10.3390/fib10040033 - 2 Apr 2022

Cited by 10 | Viewed by 3317

Abstract

This study reports the synthesis of cellulose nanocrystal (CNC) from sugarcane bagasse and rice straw as the matrix for immobilized lipase enzyme. The CNC surface was modified using cetyltrimethylammonium bromide (CTAB) to improve the interaction of CNC with glutaraldehyde so that CNC can [...] Read more.

This study reports the synthesis of cellulose nanocrystal (CNC) from sugarcane bagasse and rice straw as the matrix for immobilized lipase enzyme. The CNC surface was modified using cetyltrimethylammonium bromide (CTAB) to improve the interaction of CNC with glutaraldehyde so that CNC can immobilize lipase effectively. The results showed that after surface modification of CNC using CTAB with concentrations of 2–10 mM, the crystallinity of CNC slightly decreased. The presence of immobilized lipase on the modified CNC was confirmed visibly by the appearance of dark spots using transmission electron microscopy (TEM). The bond formed between the enzyme and CNC was approved using Fourier transform infrared spectroscopy (FTIR). FTIR results show a new amine group peak in the immobilized lipase, which is not present in the modified CNC itself. The modified CNC, both from bagasse (SB-20 A1-1) and rice straw (RS-20 B1-1), was successfully applied to the immobilized lipase enzyme with a yield of 88%. The observed free enzyme activity was 3.69 µmol/min∙mL. The degree of hydrolysis of canola oil relative to free lipase (100%) from immobilized lipase at lipase SB-20 A1-1 and lipase RS-20 A1-1 was 23% and 30%, respectively. Therefore, this study successfully immobilized lipase and applied it to the hydrolysis of triglycerides. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 4115 KiB

Open AccessArticle

Research on External Insulation Characteristics of Composite Cross-Arm of 10 kV Distribution Network Based on Multi-Factor Aging

by Zhongyuan Zhang, Junwei Qi, Hechen Liu, Wanxian Wang, Mingjia Zhang and Xuan Wu

Polymers 2022, 14(7), 1403; https://doi.org/10.3390/polym14071403 - 30 Mar 2022

Cited by 3 | Viewed by 1777

Abstract

With the application of the composite cross-arm in power systems, comprehensive anti-aging performance is a key factor to determine whether it can operate safely. In order to study the influence of the operating environment on the external insulation characteristics of composite cross-arms of [...] Read more.

With the application of the composite cross-arm in power systems, comprehensive anti-aging performance is a key factor to determine whether it can operate safely. In order to study the influence of the operating environment on the external insulation characteristics of composite cross-arms of distribution networks, various aging conditions such as voltage, rain, temperature, humidity, salt fog and ultraviolet light were simulated in a climate chamber based on the real operation conditions of the 10-kV composite cross-arm. A multi-factor aging test of composite cross-arms with two kinds of cross-section shapes (T-shaped and square) was carried out for 5000 h. The change trends of leakage current and flashover voltage of the composite cross-arms before and after aging were analyzed. Finally, the aging mechanism of the silicone rubber sheaths was analyzed to further explain the reasons for the change of external insulation performance of composite cross-arms. The results show that the leakage current rising rate of T-shaped and square composite cross-arms after aging increases significantly, and the minimum flashover voltage decreases to 58.3 kV and 49.502 kV, respectively. The results of FTIR, SEM and hydrophobic angle tests show that, after aging, the performance of the silicone rubber outer sheath material decreases in varying degrees. In general, UV aging has the greatest influence on the external insulation characteristics of composite cross arms. Generally speaking, after 5000 h of multi factor aging, although the external insulation characteristics of the 10-kV composite cross-arm decreases to a certain extent, there is still enough margin to meet the normal operation. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 25509 KiB

Open AccessArticle

Characterization of Porous Titanium-Hydroxyapatite Composite Biological Coating on Polyetheretherketone (PEEK) by Vacuum Plasma Spraying

by Fengfan Hu, Xiujuan Fan, Feng Peng, Xingchen Yan, Jinbing Song, Chunming Deng, Min Liu, Dechang Zeng and Chengyun Ning

Coatings 2022, 12(4), 433; https://doi.org/10.3390/coatings12040433 - 24 Mar 2022

Cited by 6 | Viewed by 2274

Abstract

Titanium powders and hydroxyapatite powders were used to fabricate the titanium and hydroxyapatite composite coating (Ti/Ti/HA) on the Polyetheretherketone (PEEK) by vacuum plasma spraying (VPS). The phase composition and morphology of the Ti/Ti/HA coating were analyzed by XRD, SEM, industrial CT, and three-dimensional [...] Read more.

Titanium powders and hydroxyapatite powders were used to fabricate the titanium and hydroxyapatite composite coating (Ti/Ti/HA) on the Polyetheretherketone (PEEK) by vacuum plasma spraying (VPS). The phase composition and morphology of the Ti/Ti/HA coating were analyzed by XRD, SEM, industrial CT, and three-dimensional contour profiler (DEKTAK XT). The results showed that the phase composition of the Ti/Ti/HA coating was dominated by the HA phase and a small amount of the Ti phase. The Ti/Ti/HA composite coating presented an obvious three-layer structure with different roughness and porosity. The bottom was Ti coating with a porosity less than 10%; the middle was porous Ti coating with a porosity of 35% ± 10%; the surface coating was HA coating with the crystallinity near 95%, a porosity of 32% ± 10%, a roughness Ra = 30 ± 10 μm. Moreover, the TG-DSC and ATR-FTIR results showed that VPS coating has no effect on thermochemical properties of PEEK material. The average bond strength of the composite coating was achieved 32 MPa. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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23 pages, 7795 KiB

Open AccessArticle

Multilayer Nonwoven Inserts with Aerogel/PCMs for the Improvement of Thermophysiological Comfort in Protective Clothing against the Cold

by Agnieszka Greszta, Grażyna Bartkowiak, Anna Dąbrowska, Eulalia Gliścińska, Waldemar Machnowski and Paweł Kozikowski

Materials 2022, 15(6), 2307; https://doi.org/10.3390/ma15062307 - 20 Mar 2022

Cited by 11 | Viewed by 3403

Abstract

This study aimed to assess the developed nonwoven inserts with aerogel/PCM (phase change material) microcapsules for use in protective clothing against cold in terms of properties related to thermophysiological comfort. These inserts were obtained by the thermal bonding of a multilayer system consisting [...] Read more.

This study aimed to assess the developed nonwoven inserts with aerogel/PCM (phase change material) microcapsules for use in protective clothing against cold in terms of properties related to thermophysiological comfort. These inserts were obtained by the thermal bonding of a multilayer system consisting of needled-punched nonwovens and silica aerogel particles and/or PCM microcapsules evenly distributed between them. The influence of aerogel and PCM microcapsules on the basic physical properties of inserts, their microstructure, air permeability, and water vapor resistance was investigated and analyzed. The thermal insulation properties of inserts were assessed based on thermal conductivity results. The inserts with PCMs were also tested for their ability to regulate the temperature in the undergarment microclimate using the differential scanning calorimeter (DSC) and the “skin model” device. The research showed that the use of aerogel allowed for reducing the thermal conductivity of the insert by approximately 13% compared to the insert without additives. The high values obtained of the melting and crystallization enthalpy of inserts with PCMs confirmed their high efficiency in the heat absorption and release. Thus, the use of aerogel and PCMs in protective clothing against cold seems to be an effective solution for improving its protective properties and actively adapting its thermal insulation to the changing temperature conditions and the activity level of employees. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 10468 KiB

Open AccessArticle

Effect of Low-CTE Oxide-Dispersion-Strengthened Bond Coats on Columnar-Structured YSZ Coatings

by Christoph Vorkötter, Daniel Emil Mack, Dapeng Zhou, Olivier Guillon and Robert Vaßen

Coatings 2022, 12(3), 396; https://doi.org/10.3390/coatings12030396 - 17 Mar 2022

Cited by 5 | Viewed by 2083

Abstract

Thermal barrier coatings (TBCs) are commonly used to protect gas turbine components from high temperatures and oxidation. Such coatings consist of ceramic top coats and metallic bond coats. The mismatch in thermal expansion of the top coat, the bond coat and the component [...] Read more.

Thermal barrier coatings (TBCs) are commonly used to protect gas turbine components from high temperatures and oxidation. Such coatings consist of ceramic top coats and metallic bond coats. The mismatch in thermal expansion of the top coat, the bond coat and the component material is one main factor leading to the failure of the coating system. Columnar-structured top coats offer an enhanced tolerance to the strain during thermal cycling. On a flat bond coated surface, these TBCs reach higher thermal cycling performance. However, on rough surfaces, as used for thermal spray coatings, the performance of these thermal barrier coatings seems to be restricted or even stays below the performance of atmospheric-plasma-sprayed (APS) thermal barrier coatings. This low performance is linked to out-of-plane stresses at the interface between the top coat and the bond coat. In this study, a thin additional oxide-dispersion-strengthened (ODS) bond coat with high alumina content provides a reduced mismatch of the coefficient of thermal expansion (CTE) between the top coat and the bond coat. Columnar suspension plasma sprayed (SPS), yttria-stabilized zirconia (YSZ) TBCs were combined with low-CTE ODS bond coats. The behavior of these TBCs was characterized with respect to thermal cycling performance and degradation in a burner-rig facility. The comparison showed an up-to-four-fold increase in the performance of the new system. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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99 pages, 65935 KiB

Open AccessReview

Heterogeneous Dendrimer-Based Catalysts

by Eduard Karakhanov, Anton Maximov and Anna Zolotukhina

Polymers 2022, 14(5), 981; https://doi.org/10.3390/polym14050981 - 28 Feb 2022

Cited by 9 | Viewed by 4067

Abstract

The present review compiles the advances in the dendritic catalysis within the last two decades, in particular concerning heterogeneous dendrimer-based catalysts and their and application in various processes, such as hydrogenation, oxidation, cross-coupling reactions, etc. There are considered three main approaches to the [...] Read more.

The present review compiles the advances in the dendritic catalysis within the last two decades, in particular concerning heterogeneous dendrimer-based catalysts and their and application in various processes, such as hydrogenation, oxidation, cross-coupling reactions, etc. There are considered three main approaches to the synthesis of immobilized heterogeneous dendrimer-based catalysts: (1) impregnation/adsorption on silica or carbon carriers; (2) dendrimer covalent grafting to various supports (silica, polystyrene, carbon nanotubes, porous aromatic frameworks, etc.), which may be performed in a divergent (as a gradual dendron growth on the support) or convergent way (as a grafting of whole dendrimer to the support); and (3) dendrimer cross-linking, using transition metal ions (resulting in coordination polymer networks) or bifunctional organic linkers, whose size, polarity, and rigidity define the properties of the resulted material. Additionally, magnetically separable dendritic catalysts, which can be synthesized using the three above-mentioned approaches, are also considered. Dendritic catalysts, synthesized in such ways, can be stored as powders and be easily separated from the reaction medium by filtration/centrifugation as traditional heterogeneous catalysts, maintaining efficiency as for homogeneous dendritic catalysts. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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15 pages, 4670 KiB

Open AccessArticle

Improved Cycling Performance and High Rate Capacity of LiNi_0.8Co_0.1Mn_0.1O₂ Cathode Achieved by Al(PO₃)₃ Modification via Dry Coating Ball Milling

by Feng Wang, Yikuan Luo, Peng Liu, Muhammad-Sadeeq Balogun, Jianqiu Deng and Zhongmin Wang

Coatings 2022, 12(3), 319; https://doi.org/10.3390/coatings12030319 - 28 Feb 2022

Cited by 8 | Viewed by 3513

Abstract

LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) has attracted extensive attention as a promising cathode of lithium-ion batteries (LIBs) in next-generation electric vehicles, as the NCM811 sample possesses a high energy density and a price advantage. In this work, NCM811 was [...] Read more.

LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) has attracted extensive attention as a promising cathode of lithium-ion batteries (LIBs) in next-generation electric vehicles, as the NCM811 sample possesses a high energy density and a price advantage. In this work, NCM811 was modified with an Al(PO₃)₃ precursor using the dry ball milling method followed by heat treatment to enable commercial development both at room temperature and a higher temperature. Compared with the unmodified NCM811 sample with the capacity retention of 68.70%, after Al(PO₃)₃ modification, the NCM811 sample heated to 500 °C exhibited a super capacity retention ratio of 93.88% after 200 charging–discharging cycles with the initial discharge capacity of 178.1 mAh g⁻¹ at 1 C. Additionally, after Al(PO₃)₃ modification, the NCM811 sample heated to 500 °C showed much improved rate performance compared to bare NCM811 at the current density of 5 C. The enhanced electrochemical performance after cycling was due to the decreased charge transfer resistance and increased Li⁺ transmission, which were confirmed via electrochemical impedance spectra (EIS). The NCM electrodes showed improved structural stability as layered structures after Al(PO₃)₃ modification, consistent with the improved cycling performance. This work revealed that LiNi_0.8Co_0.1Mn_0.1O₂ material with phosphide coating can be constructed using a simple ball milling method, which is feasible for obtaining high-performance electrode materials. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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6 pages, 1881 KiB

Open AccessCommunication

Facile In Situ Growth of Zif-8 Nanosheets with Enhanced Anti-Corrosion Performance for Carbon Steel in Seawater

by Zhishu Zhang, Qingjian Liu and Gaocan Qi

Coatings 2022, 12(3), 318; https://doi.org/10.3390/coatings12030318 - 28 Feb 2022

Cited by 4 | Viewed by 2439

Abstract

Carbon steel is one of the most important and widely used structural materials, but preventing its corrosion remains a great challenge. Herein, a metal–organic framework film consisting of Zif-8 nanosheets array was prepared using a one-step in situ growth method. This coating film [...] Read more.

Carbon steel is one of the most important and widely used structural materials, but preventing its corrosion remains a great challenge. Herein, a metal–organic framework film consisting of Zif-8 nanosheets array was prepared using a one-step in situ growth method. This coating film can effectively inhibit the corrosion behavior of low carbon steel in seawater, resulting in improved corrosion resistance (4010 Ω·cm⁻²) and low corrosion current density (23 μA·cm⁻²). After long-term immersion in seawater, no notable pitting corrosion was observed and the film integrity was well preserved, demonstrating the feasibility of Zif-8 film for anti-corrosion coating. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 16370 KiB

Open AccessArticle

Acoustic Insulation Mechanism of Membrane-Type Acoustic Metamaterials Loaded with Arbitrarily Shaped Mass Blocks of Variable Surface Density

by Junyu Li, Yuanyuan Shi, Renjie Jiang, Zhifu Zhang and Qibai Huang

Materials 2022, 15(4), 1556; https://doi.org/10.3390/ma15041556 - 18 Feb 2022

Cited by 13 | Viewed by 2342

Abstract

Membrane-type acoustic metamaterials (MAMs) have recently received widespread attention due to their good low-frequency sound-transmission-loss (STL) performance. A fast prediction method for the STL of rectangular membranes loaded with masses of arbitrary shapes and surface density values is proposed as a semi-analytical model [...] Read more.

Membrane-type acoustic metamaterials (MAMs) have recently received widespread attention due to their good low-frequency sound-transmission-loss (STL) performance. A fast prediction method for the STL of rectangular membranes loaded with masses of arbitrary shapes and surface density values is proposed as a semi-analytical model for calculating the STL of membrane-type acoustic metamaterials. Through conformal mapping theory, the mass blocks of arbitrary shapes were transformed into regular shapes, which simplified the calculation model of acoustic propagation loss prediction, and the prediction results were verified by finite element simulations. The results show that the change in mass surface density was closely related to the size and frequency distribution of STL. The influence of the mass center on the STL and characteristic frequency of the film metamaterial is discussed. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 6768 KiB

Open AccessArticle

Stiffness Enhancement, Anti-Aging, and Self-Forming Holes in Polycarbonate/Acrylonitrile-Styrene-Acrylic by the Core-Shell Structure of Acrylic Resin

by Ji Huang, Chunliang Kuo and Hung-Yin Tsai

Polymers 2022, 14(4), 782; https://doi.org/10.3390/polym14040782 - 17 Feb 2022

Cited by 8 | Viewed by 2684

Abstract

Currently, polycarbonate/acrylonitrile-styrene-acrylic (PC/ASA) is used mainly in the automotive, outdoor electronic equipment, sports equipment, and medical care fields, but its use is limited by its poor impact resistance and aging characteristics. This study investigates the preparation of polycarbonate/acrylonitrile-styrene-acrylic/acrylic resin (PC/ASA/ACE) via melt blending. [...] Read more.

Currently, polycarbonate/acrylonitrile-styrene-acrylic (PC/ASA) is used mainly in the automotive, outdoor electronic equipment, sports equipment, and medical care fields, but its use is limited by its poor impact resistance and aging characteristics. This study investigates the preparation of polycarbonate/acrylonitrile-styrene-acrylic/acrylic resin (PC/ASA/ACE) via melt blending. We observed that the addition of acrylic resin (ACE) enhanced the impact strength (up to 14.1%) and abrasion resistance (up to 35.7%) of the blends compared to PC/ASA. The microstructure of the copolymer was observed by scanning electron microscopy and laser scanning confocal microscopy. They were found to have a self-forming hole phenomenon, which is more favorable for potential PC/ASA applications. Furthermore, ACE addition effectively enhances the copolymer toughness and wear properties but slightly reduces their hardness, tensile strength, and melt flow rate, improving their suitability for use in applications such as aircraft windshields. After 80 cycles of aging, the PC/ASA/ACE also outperformed the impact strength of the unaged PC/ASA. ACE addition to PC/ASA can create materials with better impact and aging resistance. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 9024 KiB

Open AccessArticle

Yttrium Trifluoride as a Marker of Infiltration Rate of Decalcified Root Cementum: An In Vitro Study

by Anna Nowak-Wachol, Anna Korytkowska-Wałach, Bartosz Chmiela, Kacper Wachol, Maciej Łopaciński, Magdalena Wyszyńska, Yousuf Al-Dulaimi and Małgorzata Skucha-Nowak

Polymers 2022, 14(4), 780; https://doi.org/10.3390/polym14040780 - 17 Feb 2022

Cited by 5 | Viewed by 1869

Abstract

Research related to the development of a dental infiltrant for minimally invasive treatment of initial caries of hard dental tissues is presented. The formulation of the developed infiltrant material includes typical methacrylate monomers used in dentistry, an author’s adhesion monomer containing metronidazole, a [...] Read more.

Research related to the development of a dental infiltrant for minimally invasive treatment of initial caries of hard dental tissues is presented. The formulation of the developed infiltrant material includes typical methacrylate monomers used in dentistry, an author’s adhesion monomer containing metronidazole, a photoinitiating system and yttrium trifluoride (YF₃). The main objective of the study was to evaluate penetration into decalcified root cementum using scanning electron microscope of an experimental preparation with the characteristics of a dental infiltrant compared to a commercial preparation with the addition of YF₃ as a contrast agent. Microscopic observations showed that YF₃ particles virtually did not penetrate deep into the root cementum—this was mainly due to the particle size of YF₃. Observations of cementum and root dentin tissue infiltration: resin tissue infiltration was visible to a depth of about 80 to 120 μm without the use of a tracer, which, due to agglomeration and particle size, remained on the cementum surface or in the resin used for inlaying. There were no differences between the degree of penetration of an experimental preparation with the characteristics of a dental infiltrant, as compared to a commercial preparation. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 37376 KiB

Open AccessArticle

On the Effects of Core Microstructure on Energy Absorbing Capabilities of Sandwich Panels Intended for Additive Manufacturing

by Valerio Acanfora, Rossana Castaldo and Aniello Riccio

Materials 2022, 15(4), 1291; https://doi.org/10.3390/ma15041291 - 9 Feb 2022

Cited by 24 | Viewed by 2470

Abstract

Increasing transportation safety can be observed as one of the biggest engineering challenges. This challenge often needs to be combined with the need to deliver engineering solutions that are able to lower the environmental impact of transportation, by reducing fuel consumption. Consequentially, these [...] Read more.

Increasing transportation safety can be observed as one of the biggest engineering challenges. This challenge often needs to be combined with the need to deliver engineering solutions that are able to lower the environmental impact of transportation, by reducing fuel consumption. Consequentially, these topics have attracted considerable research efforts. The present work aims to address the previously cited challenges by maximizing the energy absorption capabilities of hybrid aluminum/composite shock absorbers with minimal thickness and mass. This engineering solution makes it possible to lighten vehicles and reduce fuel consumption, without compromising safety, in terms of crashworthiness capabilities. A numerical sensitivity study is presented, where the absorbed energy/mass (AE/m) and the absorbed energy/total panel thickness (AE/H_tot) ratios, as a consequence of low-velocity impact simulations performed on six different shock absorbers, are compared. These hybrid shock absorbers have been numerically designed by modifying the core thickness of two basic absorbers’ configurations, characterized, respectively, by a metallic lattice core, intended to be produced through additive manufacturing, and a standard metallic honeycomb core. This work provides interesting information for the development of shock absorbers, which should be further developed with an experimental approach. Indeed, it demonstrates that, by integrating composite skins with a very light core producible, by means of additive manufacturing capabilities, it is possible to design shock absorbers with excellent performance, even for very thin configurations with 6 mm thickness, and to provide a significant increase in AE/m ratios when compared to the respective equal volume standard honeycomb core configurations. This difference between the AE/m ratios of configurations with different core designs increases with the growth in volume. In detail, for configurations with a total thickness of 6 mm, the AE/m increases in additive manufacturing configurations by approximately 93%; for those with a total thickness of 10 mm, the increase is 175%, and, finally, for those with a total thickness of 14 mm, the increase is 220%. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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19 pages, 22535 KiB

Open AccessReview

Tin Diselenide (SnSe₂) Van der Waals Semiconductor: Surface Chemical Reactivity, Ambient Stability, Chemical and Optical Sensors

by Gianluca D'Olimpio, Daniel Farias, Chia-Nung Kuo, Luca Ottaviano, Chin Shan Lue, Danil W. Boukhvalov and Antonio Politano

Materials 2022, 15(3), 1154; https://doi.org/10.3390/ma15031154 - 2 Feb 2022

Cited by 13 | Viewed by 3751

Abstract

Tin diselenide (SnSe₂) is a layered semiconductor with broad application capabilities in the fields of energy storage, photocatalysis, and photodetection. Here, we correlate the physicochemical properties of this van der Waals semiconductor to sensing applications for detecting chemical species (chemosensors) and [...] Read more.

Tin diselenide (SnSe₂) is a layered semiconductor with broad application capabilities in the fields of energy storage, photocatalysis, and photodetection. Here, we correlate the physicochemical properties of this van der Waals semiconductor to sensing applications for detecting chemical species (chemosensors) and millimeter waves (terahertz photodetectors) by combining experiments of high-resolution electron energy loss spectroscopy and X-ray photoelectron spectroscopy with density functional theory. The response of the pristine, defective, and oxidized SnSe₂ surface towards H₂, H₂O, H₂S, NH₃, and NO₂ analytes was investigated. Furthermore, the effects of the thickness were assessed for monolayer, bilayer, and bulk samples of SnSe₂. The formation of a sub-nanometric SnO₂ skin over the SnSe₂ surface (self-assembled SnO₂/SnSe₂ heterostructure) corresponds to a strong adsorption of all analytes. The formation of non-covalent bonds between SnO₂ and analytes corresponds to an increase of the magnitude of the transferred charge. The theoretical model nicely fits experimental data on gas response to analytes, validating the SnO₂/SnSe₂ heterostructure as a suitable playground for sensing of noxious gases, with sensitivities of 0.43, 2.13, 0.11, 1.06 [ppm]⁻¹ for H₂, H₂S, NH₃, and NO_2, respectively. The corresponding limit of detection is 5 ppm, 10 ppb, 250 ppb, and 400 ppb for H₂, H₂S, NH₃, and NO_2, respectively. Furthermore, SnSe₂-based sensors are also suitable for fast large-area imaging applications at room temperature for millimeter waves in the THz range. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 2385 KiB

Open AccessArticle

Infrared Efficiency and Ultraviolet Management of Red-Pigmented Polymethylmethacrylate Photoselective Greenhouse Films

by Norah Alwadai and Samah El-Bashir

Polymers 2022, 14(3), 531; https://doi.org/10.3390/polym14030531 - 28 Jan 2022

Cited by 2 | Viewed by 2529

Abstract

Red-pigmented photoselective polymethylmethacrylate (PMMA) films were prepared by casting from polymer/chloroform solution. The films were doped with efficient red fluorescent perylene dyes specialized for plastic coloration, namely KREMER 94720 and KREMER 94739, which have excellent weathering stability and a high fluorescence quantum yield. [...] Read more.

Red-pigmented photoselective polymethylmethacrylate (PMMA) films were prepared by casting from polymer/chloroform solution. The films were doped with efficient red fluorescent perylene dyes specialized for plastic coloration, namely KREMER 94720 and KREMER 94739, which have excellent weathering stability and a high fluorescence quantum yield. The effect of the doping concentration was studied using the atomic force microscope (AFM), optical transmission, color measurement, time-resolved fluorescence, and Fourier transform infrared spectroscopy (FTIR). The obtained results suggested the potential usefulness for photoselective greenhouse cladding applications as the lowest doping concentration (10⁻⁵ wt%) displaying the UV-open effect, whereas the best UV-blocking and thermic effects were obtained for the highest doping concentration (10⁻¹ wt). Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 3668 KiB

Open AccessArticle

Perylene-Based Chromophore as a Versatile Dye for Light Amplification

by Alina Szukalska, Adam Szukalski, Justyna Stachera, Dorota Zajac, Ewa Chrzumnicka, Tomasz Martynski and Jaroslaw Mysliwiec

Materials 2022, 15(3), 980; https://doi.org/10.3390/ma15030980 - 27 Jan 2022

Cited by 2 | Viewed by 2035

Abstract

One of the challenges for modern optoelectronics is to find versatile, easily adaptable components for novel laser-based technologies. A very attractive perylene-derivative chromophore in different organic matrices for high-performance light amplification is discussed and outlined. Our approach demonstrates the outstandingly compatible laser dye [...] Read more.

One of the challenges for modern optoelectronics is to find versatile, easily adaptable components for novel laser-based technologies. A very attractive perylene-derivative chromophore in different organic matrices for high-performance light amplification is discussed and outlined. Our approach demonstrates the outstandingly compatible laser dye and a viable strategy to provide an effective optical gain for stimulated emission enhancement. Through structural control, we produce simple optical devices embedded in organic matrices, such as poly(methyl methacrylate), nematic liquid crystalline (NLC) mixture, and a hybrid emulsion system (poly(vinyl alcohol) PVA + NLC mesophase). Importantly, we investigate and compare the spectroscopy of differently constructed organic systems in terms of stimulated-emission thresholds and light amplification process efficiency. Moreover, we report the effects of tunability for LC cells by an applied external electric field stimulus. Future directions of laser systems are outlined with an emphasis on the role of the perylene derivative. The studies meet current challenges in the field of modern organic technologies dedicated to various optoelectronic systems, including touch screens, displays, and Li-Fi networks. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 3988 KiB

Open AccessArticle

Preparation and Comprehensive Properties of a High-Radiation-Shielding UHPC by Using Magnetite Fine Aggregate

by Jianjun Han, Zhuangmin Xi, Rui Yu, Junfeng Guan, Yajun Lv and Guo Li

Materials 2022, 15(3), 978; https://doi.org/10.3390/ma15030978 - 27 Jan 2022

Cited by 11 | Viewed by 2400

Abstract

Nuclear technology benefits humans, but it also produces nuclear radiation that harms human health and the environment. Based on the modified Andreasen and Andersen particle packing model for achieving a densely compacted cementitious matrix, a new magnetite ultra-high-performance concrete (MUHPC) was designed using [...] Read more.

Nuclear technology benefits humans, but it also produces nuclear radiation that harms human health and the environment. Based on the modified Andreasen and Andersen particle packing model for achieving a densely compacted cementitious matrix, a new magnetite ultra-high-performance concrete (MUHPC) was designed using magnetite fine aggregate as a substitute for river sands with 0%, 20%, 40%, 60%, 80%, and 100% replacement ratios. The comprehensive properties of the developed MUHPC were tested and evaluated. These properties were fluidity, static and dynamic compressive strengths, high-temperature performance, antiradiation behaviors, hydration products, and micropore structures. Experimental results indicate that the developed MUHPC has high work performance and static and dynamic mechanical properties. The gamma ray shielding performance of MUHPC substantially improves with increased magnetite fine aggregate. Corresponding with 100% magnetite fine aggregate substitution, the linear attenuation coefficient of MUHPC is enhanced by 56.8% compared with that of ordinary concrete. Magnetite addition does not change the type of cement hydration products but improves the micropore structures of MUHPC and effectively reduces its total porosity and average pore diameter, thereby contributing to its mechanical and radiation shielding properties. The compressive strength and linear attenuation coefficient of the MUHPC can reach 150 MPa and 0.2 cm⁻¹, respectively. In addition, the MUHPC also exhibits superior mechanical and radiation shielding performance at elevated temperatures (<400 °C). Finally, high strength and antiradiation performance support the use of MUHPC in radiation protection materials in the future. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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9 pages, 1983 KiB

Open AccessCommunication

Preparation and Thermal Characterization of Hollow Graphite Fibers/Paraffin Composite Phase Change Material

by Liyong Wang, Zhanjun Liu, Quangui Guo, Huiqi Wang, Xianglei Wang, Xiaozhong Dong, Xiaodong Tian and Xiaohui Guo

Coatings 2022, 12(2), 160; https://doi.org/10.3390/coatings12020160 - 27 Jan 2022

Cited by 2 | Viewed by 2464

Abstract

Paraffin is one of the most common and promising phase change materials to store and release thermal energy. The inadequacy of paraffin lies in its low thermal conductivity, which affects its further application on thermal energy storage. In this work, hollow fibers derived [...] Read more.

Paraffin is one of the most common and promising phase change materials to store and release thermal energy. The inadequacy of paraffin lies in its low thermal conductivity, which affects its further application on thermal energy storage. In this work, hollow fibers derived from pitch were spun. The graphitization (treated at 2773 K under argon atmosphere) induced the carbon atom arrangement and lattice order development, which endowed the hollow graphite fibers (HGFs) with good graphite structure. The HGFs applied as thermal additives into paraffin significantly improved its thermal conductivity. The high thermal conductivity of the HGFs/paraffin composite was achieved up to 2.50 W/(m·K) along the fiber axis, which displayed an over 680% enhancement as compared with that of the pure paraffin. The HGFs displayed significant improvement of the heat transfer rate and heat flow of paraffin, which indicated the promising potential application of the HGFs/paraffin PCM in thermal energy storage systems. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 1562 KiB

Open AccessArticle

Development and Characterization of Films for Food Application Incorporating Porphyran Extracted from Porphyra dioica

by Marco Teles, Pedro Adão, Clélia Afonso, Raul Bernardino, Mafalda Guedes, Ricardo Baptista and Susana Bernardino

Coatings 2022, 12(2), 148; https://doi.org/10.3390/coatings12020148 - 26 Jan 2022

Cited by 4 | Viewed by 2671

Abstract

Non-biodegradable plastic is one of the biggest environmental problems of our lifetime and, considering the present societal needs, it will get worse. Consequently, there is an urgent need to develop sustainable and renewable alternatives to plastic, such as plastic-like materials obtained from biodegradable [...] Read more.

Non-biodegradable plastic is one of the biggest environmental problems of our lifetime and, considering the present societal needs, it will get worse. Consequently, there is an urgent need to develop sustainable and renewable alternatives to plastic, such as plastic-like materials obtained from biodegradable polymers, namely sulfated polysaccharides, considered one of the most viable alternatives. There is also a need to obtain these materials in an environmentally and economically sustainable way. The hereby developed process of obtaining film-forming solutions from semi-refined porphyran (PorphSR) uses a green solvent (hot water) with a high extraction yield of semi-refined porphyran (26.66 ± 0.27%) in a reproducible way and with low levels of contaminants. The obtained semi-refined porphyran showed good antioxidant potential in all tests performed: HPSA (Δ0.066 ± 0.002), DPPH (2.23 ± 0.78%), FRAP (0.420 ± 0.014 eq. ascorbic acid µg mg⁻¹ of extract) and ABTS (20.46 ± 0.90%). After being cast into films, the most notable antioxidant properties were those of the semi-refined porphyran in the DPPH, FRAP and ABTS assays and of the pectin, (PorphSR_PcT and PorphSR_PcT_Gly) in the HPSA assay. Morphologically, the films showed relatively homogeneous and low roughness surfaces. It is concluded that the described method to obtain semi-refined porphyran is feasible and reproducible, and that the developed films, mainly PorfP2_PcT_Gly, proved to be a potential candidate for non-biodegradable plastic substitutes. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 34526 KiB

Open AccessArticle

Photovoltaic Device Application of a Hydroquinone-Modified Conductive Polymer and Dual-Functional Molecular Si Surface Passivation Technology

by Na Yeon Park, Gwan Seung Jeong, Young-Jin Yu, Yoon-Chae Jung, Jin Hee Lee, Jung Hwa Seo and Jea-Young Choi

Polymers 2022, 14(3), 478; https://doi.org/10.3390/polym14030478 - 25 Jan 2022

Cited by 5 | Viewed by 2935

Abstract

In the last decades, the conductive polymer PEDOT:PSS has been introduced in Si-based hybrid solar cells, gaining noticeable research interest and being considered a promising candidate for next generation solar cells which can achieve both of low manufacturing cost and high power conversion [...] Read more.

In the last decades, the conductive polymer PEDOT:PSS has been introduced in Si-based hybrid solar cells, gaining noticeable research interest and being considered a promising candidate for next generation solar cells which can achieve both of low manufacturing cost and high power conversion efficiency. This study succeeded in improving the electrical conductivity of PEDOT:PSS to 937 S/cm through a simple process of adding hydroquinone (HQ) to the pristine PEDOT:PSS solution. The results also showed that the addition of HQ to PEDOT:PSS(HQ-PEDOT:PSS) could not only dramatically improve the conductivity but also well-sustain the work function characteristics of PEDOT:PSS by promoting the formation of more continuous conductive-PEDOT channels without removing the insulating PSS. In this report, we reveal that the application of the HQ-PEDOT:PSS to the Si/PEDOT:PSS HSC could significantly improve the short-circuit current and open-circuit voltage characteristics to increase the power conversion efficiency of the HSCs compared to the conventional approaches. Moreover, we also treated the Si surface with the organic monomer, benzoquinone (BQ) to (1) passivate the excess Si surface defect states and (2) to improve the properties of the Si/PEDOT:PSS interface. We show that BQ treatment is able to dramatically increase the minority carrier lifetime induced by effective chemical and field-effect passivation in addition to enhancing the wettability of the Si surface with the PEDOT:PSS solution. As a result, the power conversion efficiency was increased by 10.6% by introducing HQ and BQ into the fabrication process of the Si/PEDOT:PSS HSC. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 9339 KiB

Open AccessArticle

Effects of Electrospinning Parameter Adjustment on the Mechanical Behavior of Poly-ε-caprolactone Vascular Scaffolds

by Anna A. Dokuchaeva, Tatyana P. Timchenko, Elena V. Karpova, Sergei V. Vladimirov, Ilya A. Soynov and Irina Y. Zhuravleva

Polymers 2022, 14(2), 349; https://doi.org/10.3390/polym14020349 - 17 Jan 2022

Cited by 9 | Viewed by 2533

Abstract

Electrospinning is a perspective method widely suggested for use in bioengineering applications, but the variability in currently available data and equipment necessitates additional research to ascertain the desirable methodology. In this study, we aimed to describe the effects of electrospinning technique alterations on [...] Read more.

Electrospinning is a perspective method widely suggested for use in bioengineering applications, but the variability in currently available data and equipment necessitates additional research to ascertain the desirable methodology. In this study, we aimed to describe the effects of electrospinning technique alterations on the structural and mechanical properties of (1,7)-polyoxepan-2-one (poly-ε-caprolactone, PCL) scaffolds, such as circumferential and longitudinal stress/strain curves, in comparison with corresponding properties of fresh rat aorta samples. Scaffolds manufactured under different electrospinning modes were analyzed and evaluated using scanning electronic microscopy as well as uniaxial longitudinal and circumferential tensile tests. Fiber diameter was shown to be the most crucial characteristic of the scaffold, correlating with its mechanical properties. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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10 pages, 2103 KiB

Open AccessArticle

Synthesis, Characterization and Biodistribution of GdF₃:Tb³⁺@RB Nanocomposites

by Oleg E. Polozhentsev, Ilia A. Pankin, Darya V. Khodakova, Pavel V. Medvedev, Anna S. Goncharova, Aleksey Yu. Maksimov, Oleg I. Kit and Alexander V. Soldatov

Materials 2022, 15(2), 569; https://doi.org/10.3390/ma15020569 - 13 Jan 2022

Cited by 5 | Viewed by 2108

Abstract

Herein we report the development of a nanocomposite for X-ray-induced photodynamic therapy (X-PDT) and computed tomography (CT) based on PEG-capped GdF₃:Tb³⁺ scintillating nanoparticles conjugated with Rose Bengal photosensitizer via electrostatic interactions. Scintillating GdF₃:Tb³⁺ nanoparticles were synthesized by [...] Read more.

Herein we report the development of a nanocomposite for X-ray-induced photodynamic therapy (X-PDT) and computed tomography (CT) based on PEG-capped GdF₃:Tb³⁺ scintillating nanoparticles conjugated with Rose Bengal photosensitizer via electrostatic interactions. Scintillating GdF₃:Tb³⁺ nanoparticles were synthesized by a facile and cost-effective wet chemical precipitation method. All synthesized nanoparticles had an elongated “spindle-like” clustered morphology with an orthorhombic structure. The structure, particle size, and morphology were determined by transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) analysis. The presence of a polyethylene glycol (PEG) coating and Rose Bengal conjugates was proved by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and ultraviolet–visible (UV-vis) analysis. Upon X-ray irradiation of the colloidal PEG-capped GdF₃:Tb³⁺–Rose Bengal nanocomposite solution, an efficient fluorescent resonant energy transfer between scintillating nanoparticles and Rose Bengal was detected. The biodistribution of the synthesized nanoparticles in mice after intravenous administration was studied by in vivo CT imaging. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 26500 KiB

Open AccessArticle

Development of Trans-1,4-Polyisoprene Shape-Memory Polymer Composites Reinforced with Carbon Nanotubes Modified by Polydopamine

by Chuang Zhang, Long Li, Yuanhang Xin, Jiaqi You, Jing Zhang, Wanlu Fu and Na Wang

Polymers 2022, 14(1), 110; https://doi.org/10.3390/polym14010110 - 29 Dec 2021

Cited by 8 | Viewed by 2079

Abstract

In this study, which was inspired by mussel-biomimetic bonding research, carbon nanotubes (CNTs) were interfacially modified with polydopamine (PDA) to prepare a novel nano-filler (CNTs@PDA). The structure and properties of the CNTs@PDA were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy [...] Read more.

In this study, which was inspired by mussel-biomimetic bonding research, carbon nanotubes (CNTs) were interfacially modified with polydopamine (PDA) to prepare a novel nano-filler (CNTs@PDA). The structure and properties of the CNTs@PDA were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The CNTs and the CNTs@PDA were used as nanofillers and melt-blended into trans-1,4 polyisoprene (TPI) to create shape-memory polymer composites. The thermal stability, mechanical properties, and shape-memory properties of the TPI/CNTs and TPI/CNTs@PDA composites were systematically studied. The results demonstrate that these modifications enhanced the interfacial interaction, thermal stability, and mechanical properties of TPI/CNTs@PDA composites while maintaining shape-memory performance. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 3691 KiB

Open AccessArticle

Two Tautomers of Thiobarbituric Acid in One Crystal: The Experimental Charge Density Perspective

by Anita M. Grześkiewicz and Maciej Kubicki

Materials 2022, 15(1), 223; https://doi.org/10.3390/ma15010223 - 28 Dec 2021

Cited by 2 | Viewed by 1396

Abstract

High-quality crystals of a certain polymorphic form of thiobarbituric acid containing both keto and enol tautomers in the asymmetric unit were obtained. High-resolution X-ray diffraction data up to sinθ/λ = 1.0 Å⁻¹ were collected and subsequently successfully used for the refining of [...] Read more.

High-quality crystals of a certain polymorphic form of thiobarbituric acid containing both keto and enol tautomers in the asymmetric unit were obtained. High-resolution X-ray diffraction data up to sinθ/λ = 1.0 Å⁻¹ were collected and subsequently successfully used for the refining of the multipolar model of electron density distribution. The use of a crystal containing both ketone and enol forms allowed a direct comparison of the topological analysis results and a closer look at the differences between these two forms. The similarities and differences between the deformation densities, electrostatic potentials, Laplacian maps and bond characteristics of the tautomers were analysed. Additionally, the spectrum of the intermolecular interactions was identified and studied from classical, relatively strong N-H···O and O-H···O hydrogen bonds through weaker N-H···S hydrogen bonds to weak interactions (for instance, C-H···O, C-H···S and N···O). The results of these studies point toward the importance of including both the geometrical features and the details of the electron density distribution in the analysis of such weak interactions. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 2002 KiB

Open AccessEditor’s ChoiceArticle

Uniaxially Strained Graphene: Structural Characteristics and G-Mode Splitting

by George Kalosakas, Nektarios N. Lathiotakis and Konstantinos Papagelis

Materials 2022, 15(1), 67; https://doi.org/10.3390/ma15010067 - 22 Dec 2021

Cited by 1 | Viewed by 3054

Abstract

The potential use of graphene in various strain engineering applications requires an accurate characterization of its properties when the material is under different mechanical loads. In this work, we present the strain dependence of the geometrical characteristics at the atomic level and the [...] Read more.

The potential use of graphene in various strain engineering applications requires an accurate characterization of its properties when the material is under different mechanical loads. In this work, we present the strain dependence of the geometrical characteristics at the atomic level and the Raman active G-band evolution in a uniaxially strained graphene monolayer, using density functional theory methods as well as molecular dynamics atomistic simulations for strains that extend up to the structural failure. The bond length and bond angle variations with strain, applied either along the zigzag or along the armchair direction, are discussed and analytical relations describing this dependence are provided. The G-mode splitting with strain, as obtained by first principles’ methods, is also presented. While for small strains, up to around 1%, the G-band splitting is symmetrical in the two perpendicular directions of tension considered here, this is no longer the case for larger values of strains where the splitting appears to be larger for strains along the zigzag direction. Further, a crossing is observed between the lower frequency split G-mode component and the out-of-plane optical mode at the Γ point for large uniaxial strains (>20%) along the zigzag direction. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 2630 KiB

Open AccessArticle

Potentiodynamic Electrochemical Impedance Spectroscopy of Polyaniline-Modified Pencil Graphite Electrodes for Selective Detection of Biochemical Trace Elements

by Adel Yavarinasab, Mostafa Abedini, Hamed Tahmooressi, Sajjad Janfaza, Nishat Tasnim and Mina Hoorfar

Polymers 2022, 14(1), 31; https://doi.org/10.3390/polym14010031 - 22 Dec 2021

Cited by 7 | Viewed by 3371

Abstract

In this study, we analyzed the application of potentiodynamic electrochemical impedance spectroscopy (PDEIS) for a selective in situ recognition of biological trace elements, i.e., Cr (III), Cu (II), and Fe (III). The electrochemical sensor was developed using the electropolymerization of aniline (Ani) on [...] Read more.

In this study, we analyzed the application of potentiodynamic electrochemical impedance spectroscopy (PDEIS) for a selective in situ recognition of biological trace elements, i.e., Cr (III), Cu (II), and Fe (III). The electrochemical sensor was developed using the electropolymerization of aniline (Ani) on the surface of the homemade pencil graphite electrodes (PGE) using cyclic voltammetry (CV). The film was overoxidized to diminish the background current. A wide range of potential (V = −0.2 V to 1.0 V) was investigated to study the impedimetric and capacitive behaviour of the PAni/modified PGE. The impedance behaviors of the films were recorded at optimum potentials through electrochemical impedance spectroscopy (EIS) and scrutinized by means of an appropriate equivalent circuit at different voltages and at their corresponding oxidative potentials. The values of the equivalent circuit were used to identify features (charge transfer-resistant and double layer capacitance) that can selectivity distinguish different trace elements with the concentration of 10 μM. The PDEIS spectra represented the highest electron transfer for Cu (II) and Cr (III) in a broad potential range between +0.1 and +0.4 V while the potential V = +0.2 V showed the lowest charge transfer resistance for Fe (III). The results of this paper showed the capability of PDEIS as a complementary tool for conventional CV and EIS measurement for metallic ion sensing. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 724 KiB

Open AccessArticle

Three-Axis Tension-Measuring Vitreoretinal Forceps Using Strain Sensor for Corneal Surgery

by Seongjin Yang, Suhyeon Kim, Seong Kyung Hong, Hyungkook Jeon, Seong J. Cho and Geunbae Lim

Polymers 2021, 13(24), 4433; https://doi.org/10.3390/polym13244433 - 17 Dec 2021

Cited by 2 | Viewed by 2705

Abstract

Precise motion control is important in robotic surgery, especially corneal surgery. This paper develops a new tension-measurement system for forceps used in corneal surgery, wherein contact force is applied only to a specific location for precise control, with precise movements detected by attaching [...] Read more.

Precise motion control is important in robotic surgery, especially corneal surgery. This paper develops a new tension-measurement system for forceps used in corneal surgery, wherein contact force is applied only to a specific location for precise control, with precise movements detected by attaching a nano-crack sensor to the corresponding part. The nano-crack sensor used here customizes the working range and sensor sensitivity to match the strain rate of the tip of the forceps. Therefore, the tension in the suture can be sufficiently measured even at suture failure. The printed circuit board attached to the bottom of the system is designed to simultaneously collect data from several sensors, visualizing the direction and magnitude of the tension in order to inform the surgeon of how much tension is being applied. This system was verified by performing pig-corneal suturing. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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21 pages, 4316 KiB

Open AccessReview

Chromophoric Dendrimer-Based Materials: An Overview of Holistic-Integrated Molecular Systems for Fluorescence Resonance Energy Transfer (FRET) Phenomenon

by Sebastián Bonardd, David Díaz Díaz, Angel Leiva and César Saldías

Polymers 2021, 13(24), 4404; https://doi.org/10.3390/polym13244404 - 15 Dec 2021

Cited by 6 | Viewed by 3430

Abstract

Dendrimers (from the Greek dendros → tree; meros → part) are macromolecules with well-defined three-dimensional and tree-like structures. Remarkably, this hyperbranched architecture is one of the most ubiquitous, prolific, and recognizable natural patterns observed in nature. The rational design and the synthesis of [...] Read more.

Dendrimers (from the Greek dendros → tree; meros → part) are macromolecules with well-defined three-dimensional and tree-like structures. Remarkably, this hyperbranched architecture is one of the most ubiquitous, prolific, and recognizable natural patterns observed in nature. The rational design and the synthesis of highly functionalized architectures have been motivated by the need to mimic synthetic and natural-light-induced energy processes. Dendrimers offer an attractive material scaffold to generate innovative, technological, and functional materials because they provide a high amount of peripherally functional groups and void nanoreservoirs. Therefore, dendrimers emerge as excellent candidates since they can play a highly relevant role as unimolecular reactors at the nanoscale, acting as versatile and sophisticated entities. In particular, they can play a key role in the properties of light-energy harvesting and non-radiative energy transfer, allowing them to function as a whole unit. Remarkably, it is possible to promote the occurrence of the FRET phenomenon to concentrate the absorbed energy in photoactive centers. Finally, we think an in-depth understanding of this mechanism allows for diverse and prolific technological applications, such as imaging, biomedical therapy, and the conversion and storage of light energy, among others. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 7479 KiB

Open AccessArticle

Study on the Complexation and Release Mechanism of Methylphenidate Hydrochloride Ion Exchange Resin Complex

by Conghui Li, Xiaolu Han, Xiaoxuan Hong, Xianfu Li, Hui Zhang, Zengming Wang and Aiping Zheng

Polymers 2021, 13(24), 4394; https://doi.org/10.3390/polym13244394 - 15 Dec 2021

Cited by 12 | Viewed by 3005

Abstract

Since the advent of ion exchange resin, it has been widely used in many fields, including drug delivery systems. The drug binds to the resin through an exchange reaction to form a drug–resin complex, which can gradually release drugs through the exchange of [...] Read more.

Since the advent of ion exchange resin, it has been widely used in many fields, including drug delivery systems. The drug binds to the resin through an exchange reaction to form a drug–resin complex, which can gradually release drugs through the exchange of physiological ions in the gastrointestinal tract, to realize functions such as taste masking and regulating release. In this study, the complexes of methylphenidate hydrochloride and Amberlite IRP69 were prepared and evaluated to explore the mechanism of complexation, influencing factors and release mechanism at a molecular level. Firstly, with the properties of the selected complexes, molecular dynamics simulation was innovatively used to find that the intermolecular interaction between drug molecules and ion exchange resin molecules is mainly caused by the stacking effect of π and salt bridges. Secondly, with the drug loading status as an indicator, the factors affecting the compounding process of the drug and resin were explored. Finally, the release mechanism of the drug–resin complex was studied by mathematical model fitting. In summary, a variety of methods were used to study the mechanism of complexation and release between drug and resin, providing a theoretical basis for promoting the marketing of ion−exchange resin−mediated oral preparations. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 21621 KiB

Open AccessArticle

Hydrophobicity and Macroscale Tribology Behavior of Stearic Acid/Hydroxypropyl Methylcellulose Dual-Layer Composite

by Shih-Chen Shi and Yao-Qing Peng

Materials 2021, 14(24), 7707; https://doi.org/10.3390/ma14247707 - 13 Dec 2021

Cited by 6 | Viewed by 2439

Abstract

Hydroxypropyl methylcellulose (HPMC) and stearic acid (SA) are integrated to fabricate a double-layer thin film composite material with potential applications in sustainable packaging and coating materials. The effect of SA concentration on the moisture and wear resistance at the macroscale of the composite [...] Read more.

Hydroxypropyl methylcellulose (HPMC) and stearic acid (SA) are integrated to fabricate a double-layer thin film composite material with potential applications in sustainable packaging and coating materials. The effect of SA concentration on the moisture and wear resistance at the macroscale of the composite are studied. The amount of SA on the surface (>SA5H) is beneficial in increasing anti-wear behavior and reducing the friction coefficient by 25%. The petal-shaped crystals formed by SA are distributed on the surface of the double-layer film, increasing its hydrophobicity. When subjected to wear, the SA crystals on the surface of the double-layer film are fractured into debris-like abrasive particles, forming an optimal third-body of moderate shape and particle size, and imparting anti-wear and lubricating characteristics. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 7937 KiB

Open AccessArticle

Design of a Non-Contact Radial Torque Sensor with Variable Torque Range by Electromagnetic Coil Coupling with Piezoelectric Sensor

by Sheng-He Wang

Materials 2021, 14(24), 7695; https://doi.org/10.3390/ma14247695 - 13 Dec 2021

Cited by 3 | Viewed by 4740

Abstract

Recently, due to the development of automation technology, torque measuring and monitoring technologies have been brought to the focus. However, the commercially available sensors have the disadvantage of large volume, which results in the difficulty of installation on existing automated machines. Responding to [...] Read more.

Recently, due to the development of automation technology, torque measuring and monitoring technologies have been brought to the focus. However, the commercially available sensors have the disadvantage of large volume, which results in the difficulty of installation on existing automated machines. Responding to the above-mentioned problem, a contactless torque sensor that uses an electromagnetic coil combined with a permanent magnet was proposed. By adjusting the input electric current in the coil, the strength of the magnetic field can be controlled to generate a non-contact magnetic force to resist external torque loading. For the measurement of such a magnetic force, a cantilever-beam mechanism comprising a piezoelectric-loading (PZT-L) sensor is employed to estimate the external static force by measuring the variation of the electric impedance. According to the measured results, the proposed PZT-L sensor demonstrates the accuracy of the proposed design, for which the maximum estimated error was around 6%. Finally, the proposed contactless torque sensor with 11 cm in diameter and 2 cm in thickness was employed to verify the effectiveness of theoretical analysis. From the sensor characteristic measurement, the detection range for external torque can be from 7.8 to 125.6 N-mm when the driven current input ranged from 2 to 10 A. Therefore, the experimental results presented that the moment of inertia via the resisted torque can be adjusted by the proposed non-contact torque-sensing system according to the measuring condition. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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9 pages, 4402 KiB

Open AccessArticle

Microstructural and Optical Properties of MgAl₂O₄ Spinel: Effects of Mechanical Activation, Y₂O₃ and Graphene Additions

by Nina Obradovic, William G. Fahrenholtz, Cole Corlett, Suzana Filipovic, Marko Nikolic, Bojan A. Marinkovic, Simone Failla, Diletta Sciti, Daniele Di Rosa and Elisa Sani

Materials 2021, 14(24), 7674; https://doi.org/10.3390/ma14247674 - 13 Dec 2021

Cited by 2 | Viewed by 2738

Abstract

Magnesium aluminate and other alumina-based spinels attract attention due to their high hardness, high mechanical strength, and low dielectric constant. MgAl₂O₄ was produced by a solid-state reaction between MgO and α-Al₂O₃ powders. Mechanical activation for 30 min [...] Read more.

Magnesium aluminate and other alumina-based spinels attract attention due to their high hardness, high mechanical strength, and low dielectric constant. MgAl₂O₄ was produced by a solid-state reaction between MgO and α-Al₂O₃ powders. Mechanical activation for 30 min in a planetary ball mill was used to increase the reactivity of powders. Yttrium oxide and graphene were added to prevent abnormal grain growth during sintering. Samples were sintered by hot pressing under vacuum at 1450 °C. Phase composition and microstructure of sintered specimens were characterized by X-ray powder diffraction and scanning electron microscopy. Rietveld analysis revealed 100% pure spinel phase in all sintered specimens, and a decrease in crystallite size with the addition of yttria or graphene. Density measurements indicated that the mechanically activated specimen reached 99.6% relative density. Furthermore, the highest solar absorbance and highest spectral selectivity as a function of temperature were detected for the mechanically activated specimen with graphene addition. Mechanical activation is an efficient method to improve densification of MgAl₂O₄ prepared from mixed oxide powders, while additives improve microstructure and optical properties. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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10 pages, 10661 KiB

Open AccessArticle

Investigation of Carbon-Based Composites for Elastic Heaters and Effects of Hot Pressing in Thermal Transfer Process on Thermal and Electrical Properties

by Tomasz Raczyński, Daniel Janczak, Jerzy Szałapak, Piotr Walter and Małgorzata Jakubowska

Materials 2021, 14(24), 7606; https://doi.org/10.3390/ma14247606 - 10 Dec 2021

Cited by 5 | Viewed by 2130

Abstract

Wearable electronics are new structures with a wide range of possible applications. This study aims to analyze the effects of hot pressing in thermal transfer of different carbon-based composites as a new application method of screen-printed electronics on textiles. Flexible heaters were screen-printed [...] Read more.

Wearable electronics are new structures with a wide range of possible applications. This study aims to analyze the effects of hot pressing in thermal transfer of different carbon-based composites as a new application method of screen-printed electronics on textiles. Flexible heaters were screen-printed on polyethylene terephthalate PET foil with composites based on graphene, carbon black, and graphite with different wt.%, measured and then hot pressed to measure and analyze differences. Research showed that the hot pressing process in thermal transfer resulted in decreased electrical resistance, increased power, and higher maximal temperatures. Best results were achieved with composites based on 12 wt.% graphene with sheet resistance lowered by about 40% and increased power by about 110%. This study shows promise for thermal transfer and screen-printing combination as an alternative for creating flexible electronics on textiles. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 2257 KiB

Open AccessArticle

Eco Friendly Synthesis of Carbon Dot by Hydrothermal Method for Metal Ions Salt Identification

by Hasan Shabbir, Tomasz Tokarski, Ditta Ungor and Marek Wojnicki

Materials 2021, 14(24), 7604; https://doi.org/10.3390/ma14247604 - 10 Dec 2021

Cited by 19 | Viewed by 3231

Abstract

In this work, we report the synthesis method of carbon quantum dots (CDs) using the one-step method for fast and effective metal ion determination. Ascorbic acid was used as an inexpensive and environmentally friendly precursor. High-pressure and high-temperature reactors were used for this [...] Read more.

In this work, we report the synthesis method of carbon quantum dots (CDs) using the one-step method for fast and effective metal ion determination. Ascorbic acid was used as an inexpensive and environmentally friendly precursor. High-pressure and high-temperature reactors were used for this purpose. Microscopic characterization revealed the size of CDs was in the range of 2–6 nm and they had an ordered structure. The photoluminescence properties of the CDs depend on the process temperature, and we obtained the highest PL spectra for 6 h of hydrothermal reaction. The maximum emission spectra depend poorly on synthesis time. Further characterization shows that CDs are a good contender for sensing Fe³⁺ in aqueous systems and can detect concentrations up to 0.49 ppm. The emission spectra efficiency was enhanced by up to 200% with synthesis time. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 20783 KiB

Open AccessArticle

Preparation of Mn²⁺ Doped Piperazine Phosphate as a Char-Forming Agent for Improving the Fire Safety of Polypropylene/Ammonium Polyphosphate Composites

by Fuqiang Dong, Zhonglin Luo and Biaobing Wang

Materials 2021, 14(24), 7589; https://doi.org/10.3390/ma14247589 - 10 Dec 2021

Cited by 4 | Viewed by 2633

Abstract

A piperazine phosphate doped with Mn²⁺ (HP-Mn), as a new char-forming agent for intumescent flame retardant systems (IFR), was designed and synthesized using 1-hydroxy ethylidene-1,1-diphosphonic acid, piperazine, and manganese acetate tetrahydrate as raw materials. The effect of HP-Mn and ammonium polyphosphate (APP) [...] Read more.

A piperazine phosphate doped with Mn²⁺ (HP-Mn), as a new char-forming agent for intumescent flame retardant systems (IFR), was designed and synthesized using 1-hydroxy ethylidene-1,1-diphosphonic acid, piperazine, and manganese acetate tetrahydrate as raw materials. The effect of HP-Mn and ammonium polyphosphate (APP) on the fire safety and thermal stability of polypropylene (PP) was investigated. The results showed that the combined incorporation of 25 wt.% APP/HP-Mn at a ratio of 1:1 endowed the flame retardant PP (PP6) composite with the limiting oxygen index (LOI) of 30.7% and UL-94 V-0 rating. In comparison with the pure PP, the peak heat release rate (PHRR), the total heat release (THR), and the smoke production rate (PSPR) of the PP6 were reduced by 74%, 30%, and 70%, respectively. SEM and Raman analysis of the char residues demonstrated that the Mn²⁺ displayed a catalytic cross-linking charring ability to form a continuous and compact carbon layer with a high degree of graphitization, which can effectively improve the flame retardancy of PP/APP composites. A possible flame-retardant mechanism was proposed to reveal the synergistic effect between APP and HP-Mn. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 4551 KiB

Open AccessArticle

Enhanced Strength and Plasticity of CoCrNiAl_0.1Si_0.1 Medium Entropy Alloy via Deformation Twinning and Microband at Cryogenic Temperature

by Xiao-Hua Gu, Yu-Quan Meng, Hui Chang, Tian-Xiang Bai, Sheng-Guo Ma, Yong-Qiang Zhang, Wei-Dong Song and Zhi-Qiang Li

Materials 2021, 14(24), 7574; https://doi.org/10.3390/ma14247574 - 9 Dec 2021

Cited by 1 | Viewed by 2539

Abstract

The synthesis of lightweight yet strong-ductile materials has been an imperative challenge in alloy design. In this study, the CoCrNi-based medium-entropy alloys (MEAs) with added Al and Si were manufactured by vacuum arc melting furnace subsequently followed by cool rolling and anneal process. [...] Read more.

The synthesis of lightweight yet strong-ductile materials has been an imperative challenge in alloy design. In this study, the CoCrNi-based medium-entropy alloys (MEAs) with added Al and Si were manufactured by vacuum arc melting furnace subsequently followed by cool rolling and anneal process. The mechanical responses of CoCrNiAl_0.1Si_0.1 MEAs under quasi-static (1 × 10⁻³ s⁻¹) tensile strength showed that MEAs had an outstanding balance of yield strength, ultimate tensile strength, and elongation. The yield strength, ultimate tensile strength, and elongation were increased from 480 MPa, 900 MPa, and 58% at 298 K to 700 MPa, 1250 MPa, and 72% at 77 K, respectively. Temperature dependencies of the yield strength and strain hardening were investigated to understand the excellent mechanical performance, considering the contribution of lattice distortions, deformation twins, and microbands. Severe lattice distortions were determined to play a predominant role in the temperature-dependent yield stress. The Peierls barrier height increased with decreasing temperature, owing to thermal vibrations causing the effective width of a dislocation core to decrease. Through the thermodynamic formula, the stacking fault energies were calculated to be 14.12 mJ/m² and 8.32 mJ/m² at 298 K and 77 K, respectively. In conclusion, the enhanced strength and ductility at cryogenic temperature can be attributed to multiple deformation mechanisms including dislocations, extensive deformation twins, and microbands. The synergistic effect of multiple deformation mechanisms lead to the outstanding mechanical properties of the alloy at room and cryogenic temperature. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 3743 KiB

Open AccessArticle

Selenium-Functionalized Corn Starch as a Biodegradable GPx Mimic with High Catalytic Performance

by Shufei Jiao, Zijie Liu, Min Liu, Yongxian Liu, Shuming Zhong, Feng Wang and Yanzhen Yin

Polymers 2021, 13(24), 4309; https://doi.org/10.3390/polym13244309 - 9 Dec 2021

Viewed by 2460

Abstract

Selenium-functionalized starch (Se-starch80) is one of the main functional foods used for selenium supplementation. In traditional agriculture, Se-starch has some deficiencies such as long growth cycle and unstable selenium content that prevent its antioxidant performance. In this study, Se-starch was prepared by the [...] Read more.

Selenium-functionalized starch (Se-starch80) is one of the main functional foods used for selenium supplementation. In traditional agriculture, Se-starch has some deficiencies such as long growth cycle and unstable selenium content that prevent its antioxidant performance. In this study, Se-starch was prepared by the nucleophilic addition between NaSeH and carbon-carbon double bond of octenyl succinic anhydride waxy corn starch ester (OSA starch). Some techniques such as ¹HNMR, XPS, SEM-EDS, XRD and FT-IR were used to characterize the relevant samples and the results showed that the modification did not destroy the starch framework significantly and the catalytic center (negative divalent selenium) was anchored on the starch framework. The intensive distribution of catalytic center on the starch surface and the hydrophobic microenvironments derived from the OSA chains furnished the Se-starch80 with a high GPx-like catalytic activity (initial reaction rate = 3.64 μM/min). This value was about 1.5 × 10⁵ times higher than that of a typical small-molecule GPx mimic (PhSeSePh). In addition, the Se-starch80, without any cytotoxicity, showed a saturated kinetic catalytic behavior that is similar to a typical enzyme. This work exemplifies a biodegradable selenium-functionalized polymer platform for the high-performing GPx mimic. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 3253 KiB

Open AccessArticle

Trimethoprim Antibiotic Adsorption from Aqueous Solution onto Eco-Friendly Zr-Metal Organic Framework Material

by Marwa Elkady, Kamal E. Diab and Hassan Shokry

Materials 2021, 14(24), 7545; https://doi.org/10.3390/ma14247545 - 8 Dec 2021

Cited by 9 | Viewed by 2358

Abstract

The synthesis of Bio-MOF using aspartic acid as an organic linker and water as a solvent was performed to create an environmentally friendly material. The chemical composition, structure, and morphology of the synthesized zirconium Bio-MOF (MIP-202) was evaluated using X-ray diffraction (XRD), energy [...] Read more.

The synthesis of Bio-MOF using aspartic acid as an organic linker and water as a solvent was performed to create an environmentally friendly material. The chemical composition, structure, and morphology of the synthesized zirconium Bio-MOF (MIP-202) was evaluated using X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The synthesized Bio-MOF was used as an adsorbent for trimethoprim antibiotic as pollutants from an aqueous solution under various operating parameters. The increase in the initial trimethoprim concentration from 2.5 mg/L to 20 mg/L decreased the decontamination efficiency from 77.6% to 35.9% at a solution pH of 7 with 0.5 g/L adsorbent dose after 60 min reaction time. The rise of adsorbent dose from 0.1 g/L to 1.5 g/L increased the removal efficiency from 47.7% to 87.6%. The maximum trimethoprim removal efficiency of 95% was attained at a solution pH of 11. Langmuir and pseudo-second order models described the adsorption process of trimethoprim antibiotic onto zirconium Bio-MOF and the chemo-physical nature of trimethoprim adsorption onto the synthesized zirconium Bio-MOF. Accordingly, it was evident that the prepared zirconium Bio-MOF (MIP-202) is an ecofriendly and efficient adsorbent for antibiotic decontamination from polluted water. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 3830 KiB

Open AccessArticle

Fabrication of Millable Polyurethane Elastomer/Eucommia Ulmoides Rubber Composites with Superior Sound Absorption Performance

by Yuhang Dong, Dexian Yin, Linhui Deng, Renwei Cao, Shikai Hu, Xiuying Zhao and Li Liu

Materials 2021, 14(23), 7487; https://doi.org/10.3390/ma14237487 - 6 Dec 2021

Cited by 6 | Viewed by 2408

Abstract

Sound absorbing materials combining millable polyurethane elastomer (MPU) and eucommia ulmoides rubber (EUG) were successfully fabricated via a physical blending process of EUG and MPU. The microstructure, crystallization performances, damping, mechanical and sound absorption properties of the prepared MPU/EUG composites were investigated systematically. [...] Read more.

Sound absorbing materials combining millable polyurethane elastomer (MPU) and eucommia ulmoides rubber (EUG) were successfully fabricated via a physical blending process of EUG and MPU. The microstructure, crystallization performances, damping, mechanical and sound absorption properties of the prepared MPU/EUG composites were investigated systematically. The microstructure surface of various MPU/EUG composites became rough and cracked by the gradual incorporation of EUG, resulting in a deteriorated compatibility between EUG and MPU. With the increase of EUG content, the storage modulus (E’) of various MPU/EUG composites increased in a temperature range of −50 °C to 40 °C and their loss factor (tanδ) decreased significantly, including a reduction of the tanδ of MPU/EUG (70/30) composites from 0.79 to 0.64. Specifically, the addition of EUG sharply improved the sound absorption performances of various MPU/EUG composites in a frequency range of 4.5 kHz–8 kHz. Compared with that of pure MPU, the sound absorption coefficient of the MPU/EUG (70/30) composite increased 52.2% at a pressure of 0.1 MPa and 16.8% at a pressure of 4 MPa, indicating its outstanding sound absorption properties. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 3024 KiB

Open AccessArticle

Evaluation of the Biocompatibility and Endothelial Differentiation Capacity of Mesenchymal Stem Cells by Polyethylene Glycol Nanogold Composites

by Huey-Shan Hung, Yi-Chin Yang, Wei-Chien Kao, Chun-An Yeh, Kai-Bo Chang, Cheng-Ming Tang, Hsien-Hsu Hsieh and Hsu-Tung Lee

Polymers 2021, 13(23), 4265; https://doi.org/10.3390/polym13234265 - 6 Dec 2021

Cited by 4 | Viewed by 3007

Abstract

Cardiovascular Diseases (CVDs) such as atherosclerosis, where inflammation occurs in the blood vessel wall, are one of the major causes of death worldwide. Mesenchymal Stem Cells (MSCs)-based treatment coupled with nanoparticles is considered to be a potential and promising therapeutic strategy for vascular [...] Read more.

Cardiovascular Diseases (CVDs) such as atherosclerosis, where inflammation occurs in the blood vessel wall, are one of the major causes of death worldwide. Mesenchymal Stem Cells (MSCs)-based treatment coupled with nanoparticles is considered to be a potential and promising therapeutic strategy for vascular regeneration. Thus, angiogenesis enhanced by nanoparticles is of critical concern. In this study, Polyethylene Glycol (PEG) incorporated with 43.5 ppm of gold (Au) nanoparticles was prepared for the evaluation of biological effects through in vitro and in vivo assessments. The physicochemical properties of PEG and PEG–Au nanocomposites were first characterized by UV-Vis spectrophotometry (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and Atomic Force Microscopy (AFMs). Furthermore, the reactive oxygen species scavenger ability as well as the hydrophilic property of the nanocomposites were also investigated. Afterwards, the biocompatibility and biological functions of the PEG–Au nanocomposites were evaluated through in vitro assays. The thin coating of PEG containing 43.5 ppm of Au nanoparticles induced the least platelet and monocyte activation. Additionally, the cell behavior of MSCs on PEG–Au 43.5 ppm coating demonstrated better cell proliferation, low ROS generation, and enhancement of cell migration, as well as protein expression of the endothelialization marker CD31, which is associated with angiogenesis capacity. Furthermore, anti-inflammatory and endothelial differentiation ability were both evaluated through in vivo assessments. The evidence demonstrated that PEG–Au 43.5 ppm implantation inhibited capsule formation and facilitated the expression of CD31 in rat models. TUNEL assay also indicated that PEG–Au nanocomposites would not induce significant cell apoptosis. The above results elucidate that the surface modification of PEG–Au nanomaterials may enable them to serve as efficient tools for vascular regeneration grafts. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 29233 KiB

Open AccessArticle

The Impact of Artificial Marble Wastes on Heat Deflection Temperature, Crystallization, and Impact Properties of Polybutylene Terephthalate

by Tianliang Feng, Yangzhou Li, Liang Fang and Zhenming Chen

Polymers 2021, 13(23), 4242; https://doi.org/10.3390/polym13234242 - 3 Dec 2021

Cited by 3 | Viewed by 2132

Abstract

As artificial marble is abundant and widely used in residential and commercial fields, the resource utilization of artificial marble wastes (AMWs) has become extremely important in order to protect the environment. In this paper, polybutylene terephthalate/artificial marble wastes (PBT/AMWs) composites were prepared by [...] Read more.

As artificial marble is abundant and widely used in residential and commercial fields, the resource utilization of artificial marble wastes (AMWs) has become extremely important in order to protect the environment. In this paper, polybutylene terephthalate/artificial marble wastes (PBT/AMWs) composites were prepared by melt blending to maximize resource utilization and increase PBT performance. The research results showed that the filling of AMWs was beneficial to the improvement of PBT-related performance. X-ray diffraction analysis results indicated that after filling AMWs into the PBT matrix, the crystal structure of PBT was not changed. Heat deflection temperature (HDT) analysis results indicated that the HDT of PBT composites with 20 wt% AMWs reached 66.68 °C, which was 9.12 °C higher than that of neat PBT. Differential scanning calorimetry analysis results showed that heterogeneous nucleation could be well achieved when the filling content was 15 wt%; impact and scanning electron microscope analysis results showed that due to the partial core-shell structure of the AMWs, the impact strength of PBT was significantly improved after filling. When the filling amount was 20 wt%, the impact strength of the PBT composites reached 23.20 kJ/m², which was 17.94 kJ/m² higher than that of neat PBT. This research will not only provide new insights into the efficient and high-value utilization of AMWs, but also provide a good reference for improved applications of other polymers. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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22 pages, 10170 KiB

Open AccessArticle

Investigation into the Integration of Impregnated Glass and Carbon Textiles in a Laboratory Mortar Extruder (LabMorTex)

by Matthias Kalthoff, Michael Raupach and Thomas Matschei

Materials 2021, 14(23), 7406; https://doi.org/10.3390/ma14237406 - 2 Dec 2021

Cited by 14 | Viewed by 2389

Abstract

A promising process for the automatization of concrete structures is extrusion or extrusion molding. An innovative approach is the extrusion of concrete with imbedded technical textiles as reinforcement. For a successful extrusion, the rheological properties of the fresh concrete have to be optimized, [...] Read more.

A promising process for the automatization of concrete structures is extrusion or extrusion molding. An innovative approach is the extrusion of concrete with imbedded technical textiles as reinforcement. For a successful extrusion, the rheological properties of the fresh concrete have to be optimized, as it must be extrudable and have sufficient early strength after leaving the mouthpiece. Within the scope of this paper, a process was developed which allows the integration of flexible as well as stiff impregnated textiles into the extrusion process. For this purpose, different textile-reinforced mortars (TRM) were extruded and their material characteristics were investigated. The results show that the mortar cross-section is considerably strengthened, especially when using carbon textiles, and that extrusion has considerable potential to produce high-performance TRM composites. In uniaxial tension tests with TRM, as well as in the pure roving tensile strength tests, textile stresses of approx. 1200 MPa were achieved for the glass textile and approx. 2250 MPa for the carbon textile. The position of the textile layer deviated a maximal 0.4 mm from its predesigned position, which shows its potential for producing tailor-made TRM elements. In addition, by adjusting the mortar mix design, it was possible to reduce the global warming potential (GWP) of the extrusion compound by up to 49.3% compared to the initial composition from preliminary studies. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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10 pages, 3444 KiB

Open AccessArticle

Facile and Controllable Preparation of Poly(St-co-MMA)/FA Microspheres Used as Ultra-Lightweight Proppants

by Tao Chen, Yanan Sang, Yuxin Zhou, Liudi Ji, Xiaobing Han, Peng Hu, Pengpai Miao, Jie Gao and Yuan Zhao

Materials 2021, 14(23), 7390; https://doi.org/10.3390/ma14237390 - 2 Dec 2021

Cited by 9 | Viewed by 1852

Abstract

Hydraulic fracturing is an important technology for the exploitation of unconventional oil or gas reservoirs. In order to increase the production of oil or gas, ultra-lightweight proppants with a high compressive strength are highly desirable in hydraulic fracture systems. In this work, a [...] Read more.

Hydraulic fracturing is an important technology for the exploitation of unconventional oil or gas reservoirs. In order to increase the production of oil or gas, ultra-lightweight proppants with a high compressive strength are highly desirable in hydraulic fracture systems. In this work, a new type of ultra-lightweight proppant, poly(styrene-co-methyl methacrylate)/fly ash (poly(St-co-MMA)/FA) composites with a high compressive strength were prepared via in situ suspension polymerization. The Fourier transform infrared (IR) and X-ray powder diffraction (XRD) analyses confirmed that the poly(St-co-MMA)/FA composites were successfully prepared. The morphology analysis indicated that the composite microspheres show good sphericity, and FA powder was evenly dispersed in the matrix. The apparent density of the microspheres was between 1 and 1.3 g/cm³, which is suitable for hydraulic fracturing. Furthermore, the compressive strength and thermostability were dramatically improved with the incorporation of FA, which could withstand high pressures and temperatures underground. The obtained poly(St-co-MMA)/FA composite microspheres are promising for application as an ultra-lightweight (ULW) proppant in oil or gas exploitation, which provides a new approach for the design of high performance proppants. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 3692 KiB

Open AccessArticle

Two Birds with One Stone: Preparation of 4, 4-Diaminodiphenylmethane Functionalized GO@SiO₂ with Mechanical Reinforcement and UV Shielding Properties and Its Application in Thermoplastic Polyurethane

by Guoxin Ding, Hongxu Tai, Chuanxin Chen, Chenfeng Sun and Zhongfeng Tang

Polymers 2021, 13(23), 4220; https://doi.org/10.3390/polym13234220 - 1 Dec 2021

Cited by 2 | Viewed by 2182

Abstract

This study prepared 4,4-diaminodiphenylmethane (DDM)-functionalized graphene oxide (GO)@silica dioxide (SiO₂) nano-composites through amidation reaction and low-temperature precipitation. The resulting modified GO, that was DDM−GO@SiO₂. The study found that DDM−GO@SiO₂ showed good dispersion and compatibility with thermoplastic polyurethane (TPU) [...] Read more.

This study prepared 4,4-diaminodiphenylmethane (DDM)-functionalized graphene oxide (GO)@silica dioxide (SiO₂) nano-composites through amidation reaction and low-temperature precipitation. The resulting modified GO, that was DDM−GO@SiO₂. The study found that DDM−GO@SiO₂ showed good dispersion and compatibility with thermoplastic polyurethane (TPU) substrates. Compared with pure TPU, the tensile strength of the TPU composites increased by 41% to 94.6 MPa at only 0.5 wt% DDM−GO@SiO₂. In addition, even when a small amount of DDM−GO@SiO₂ was added, the UV absorption of TPU composites increased significantly, TPU composites can achieve a UV shielding efficiency of 95.21% in the UV-A region. These results show that this type of material holds great promise for the preparation of functional coatings and film materials with high strength and weather resistance. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 5588 KiB

Open AccessArticle

Broadband Bi-Directional Polarization-Insensitive Metamaterial Absorber

by Feng Tian, Xia Ma, Han Hao, Xuewen Li, Jingdao Fan, Liang Guo and Xiaojun Huang

Materials 2021, 14(23), 7339; https://doi.org/10.3390/ma14237339 - 30 Nov 2021

Cited by 4 | Viewed by 2254

Abstract

Conventional metamaterial absorbers eliminate the transmitted electromagnetic wave by attaching the metal plate with the unidirectional absorption performance; these absorbers limit the practical applications to a large extent. In this paper, we present a broadband bi-directional metamaterial absorber by etching chip resistors on [...] Read more.

Conventional metamaterial absorbers eliminate the transmitted electromagnetic wave by attaching the metal plate with the unidirectional absorption performance; these absorbers limit the practical applications to a large extent. In this paper, we present a broadband bi-directional metamaterial absorber by etching chip resistors on the resonators for expanding the bandwidth, and two orthogonal I-shaped structures are pasted on the both sides of the ultra-thin substrate (FR-4) instead of the metal plate for enhancing absorptance of the absorber. Simulated results show that absorptance of the designed absorber is larger than 0.9 in 1.43–2.51 GHz along the forward and backward directions under both TE and TM polarizations. Microwave experiments in the chamber are performed to verify the simulations, and the experimental results exhibit the excellent agreement with the simulations. Additionally, two I-shaped structures are orthogonally pasted on an ultrathin substrate, leading to the impedance-matching of both forward and backward directions, and the absorptance can be tailed dynamically via the middle layer of the substrate. The physics of the absorption are visualized by using a transmission line based on equivalent circuits. We claim that the designed bi-directional metamaterial absorber can be a good candidate for electromagnetic stealth and energy harvesting. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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10 pages, 4022 KiB

Open AccessArticle

Comparison of Precursor Preparation Routes on Final Density of Y₃Fe₅O₁₂ Garnets Prepared via Reactive Sintering

by Kamil Wojciechowski, Radosław Lach, Magdalena Stan, Łukasz Łańcucki, Marta Gajewska and Dariusz Zientara

Materials 2021, 14(23), 7316; https://doi.org/10.3390/ma14237316 - 29 Nov 2021

Cited by 1 | Viewed by 1674

Abstract

Yttrium iron garnet was obtained using four methods of synthesis. A modified citrate method and a modified citrate method with YIG (yttrium iron garnet, Y₃Fe₅O₁₂) nucleation were used. In two subsequent methods, YIP (yttrium iron perovskite, YFeO [...] Read more.

Yttrium iron garnet was obtained using four methods of synthesis. A modified citrate method and a modified citrate method with YIG (yttrium iron garnet, Y₃Fe₅O₁₂) nucleation were used. In two subsequent methods, YIP (yttrium iron perovskite, YFeO₃) and α-Fe₂O₃ obtained in the first case by the citrate method and in the second by precipitation of precursors with an ammonia solution were used as the input precursors for reaction sintering. Differential scanning calorimetry (DSC) measurements of the output powders obtained by all methods allowed to identify the effects observed during the temperature increase. Dilatometric measurements allowed to determine the changes in linear dimensions at individual stages of reaction sintering. In the case of materials obtained by the citrate method, two effects occur with the increasing temperature, the first of which corresponds to the reaction of the formation of yttrium iron perovskite (YIP), and the second is responsible for the reaction of the garnet (YIG) formation. However, in the case of heat treatment of the mixture of YIP and α-Fe₂O₃, we observe only the effect responsible for the solid state reaction leading to the formation of yttrium iron garnet. The obtained materials were reaction sintered at temperatures of 1300 and 1400 °C. Only in the case of material obtained from a mixture of perovskite and iron(III) oxide obtained by ammonia precipitation at temperature of 1400 °C were densities achieved higher than 98% of the theoretical density. The use of Hot Isostatic Pressing (HIP) in the case of this material allowed to eliminate the remaining porosity and to obtain full density. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 5119 KiB

Open AccessArticle

Investigation on the Thermodynamic Stability of Nanocrystalline W-Based Alloys: A Combined Theoretical and Experimental Approach

by Francesco Torre, Claudio Mingazzini, Daniele Mirabile Gattia, Teodor Huminiuc, Antonio Rinaldi, Tomas Polcar, Francesco Delogu and Antonio Mario Locci

Materials 2021, 14(23), 7179; https://doi.org/10.3390/ma14237179 - 25 Nov 2021

Cited by 1 | Viewed by 3228

Abstract

The stability of nanostructured metal alloys is currently being extensively investigated, and several mathematical models have been developed to describe the thermodynamics of these systems. However, model capability in terms of thermal stability predictions strongly relies on grain boundary-related parameters that are difficult [...] Read more.

The stability of nanostructured metal alloys is currently being extensively investigated, and several mathematical models have been developed to describe the thermodynamics of these systems. However, model capability in terms of thermal stability predictions strongly relies on grain boundary-related parameters that are difficult to measure or estimate accurately. To overcome this limitation, a novel theoretical approach is proposed and adopted in this work to identify W-based nanocrystalline alloys which are potentially able to show thermodynamic stability. A comparison between model outcomes and experimental findings is reported for two selected alloys, namely W-Ag and W-Al. Experimental results clearly highlight that W-Ag mixtures retain a segregated structure on relatively coarse length scales even after prolonged mechanical treatments. Moreover, annealing at moderate temperatures readily induces demixing of the constituent elements. In contrast, homogeneous nanostructured W-Al solid solutions are obtained by ball milling of elemental powders. These alloys show enhanced thermal stability with respect to pure W even at high homologous temperatures. Experimental evidences agree with model predictions for both the investigated systems. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 4270 KiB

Open AccessArticle

Accuracy in Cement Hydration Investigations: Combined X-ray Microtomography and Powder Diffraction Analyses

by Inés R. Salcedo, Ana Cuesta, Shiva Shirani, Laura León-Reina and Miguel A. G. Aranda

Materials 2021, 14(22), 6953; https://doi.org/10.3390/ma14226953 - 17 Nov 2021

Cited by 6 | Viewed by 2738

Abstract

Cement hydration is a very complex set of processes. The evolution of the crystalline phases during hydration can be accurately followed by X-ray powder diffraction data evaluated by the Rietveld method. However, accurate measurements of some microstructural features, including porosity and amorphous content [...] Read more.

Cement hydration is a very complex set of processes. The evolution of the crystalline phases during hydration can be accurately followed by X-ray powder diffraction data evaluated by the Rietveld method. However, accurate measurements of some microstructural features, including porosity and amorphous content developments, are more challenging. Here, we combine laboratory X-ray powder diffraction and computed microtomography (μCT) to better understand the results of the μCT analyses. Two pastes with different water–cement ratios, 0.45 and 0.65, filled within capillaries of two sizes, ϕ = 0.5 and 1.0 mm, were analysed at 50 days of hydration. It was shown that within the spatial resolution of the measured μCTs, ~2 μm, the water capillary porosity was segmented within the hydrated component fraction. The unhydrated part could be accurately quantified within 2 vol% error. This work is a first step to accurately determining selected hydration features like the hydration degree of amorphous phases of supplementary cementitious materials within cement blends. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 3596 KiB

Open AccessArticle

Thermodynamic Coupling Simulation of CrN/Cr Composite Coating Barrel Bore

by Shaowei Wang, Chuanbin Wang and Wenjun Li

Coatings 2021, 11(11), 1358; https://doi.org/10.3390/coatings11111358 - 4 Nov 2021

Cited by 2 | Viewed by 2295

Abstract

The barrel is the core component of the artillery, and its inner coating is the key material to effectively protect the barrel and improve its service lifetime. Due to its good properties, CrN/Cr composite is a potential alternative to the currently used Cr [...] Read more.

The barrel is the core component of the artillery, and its inner coating is the key material to effectively protect the barrel and improve its service lifetime. Due to its good properties, CrN/Cr composite is a potential alternative to the currently used Cr coating. In this study, finite element simulation has been performed using the software Ansys Workbench to analyze the temperature field and coupled stress field of the Cr coating barrel and the CrN/Cr composite coating barrel, respectively, during the firing. The results showed that compared with Cr coating barrel, the CrN/Cr coating can reduce the temperature and significantly mitigate the stress in the coating/steel matrix interface; thus, it is expected the CrN/Cr coating can better protect the artillery barrel. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 3485 KiB

Open AccessArticle

The Influence of the Microstructure of Ceramic-Elastomer Composites on Their Energy Absorption Capability

by Paulina Kozera, Anna Boczkowska, Rafał Kozera, Marcin Małek and Włodzimierz Idczak

Materials 2021, 14(21), 6618; https://doi.org/10.3390/ma14216618 - 3 Nov 2021

Cited by 3 | Viewed by 1909

Abstract

The paper presents the experimental results of static and dynamic compressive tests conducted on ceramic-elastomer composites. The alumina ceramic preforms were fabricated by the four-step method: ceramic mixture preparation, consolidation under pressure, presintering, and sintering under pressure, respectively. To obtain ceramic preforms with [...] Read more.

The paper presents the experimental results of static and dynamic compressive tests conducted on ceramic-elastomer composites. The alumina ceramic preforms were fabricated by the four-step method: ceramic mixture preparation, consolidation under pressure, presintering, and sintering under pressure, respectively. To obtain ceramic preforms with a similar volume fraction of open pores, but with different pore sizes, alumina powder with different particle size and a ceramic binder were used, as well as pore-forming agents that were evenly distributed throughout the volume of the molding mass. The composites were obtained using vacuum pressure infiltration of porous alumina ceramic by urea-urethane elastomer in liquid form. As a result, the obtained composites were characterized by two phases that interpenetrated three-dimensionally and topologically throughout the microstructure. The microstructure of the ceramic preforms was revealed by X-ray tomography, which indicated that the alumina preforms had similar porosity of approximately 40% vol. but different pore diameter in the range of 6 to 34 µm. After composite fabrication, image analysis was carried out. Due to the microstructure of the ceramic preforms, the composites differed in the specific surface fraction of the interphase boundaries (S_v). The highest value of the S_v parameter was achieved for composite fabricated by infiltration method of using ceramic preform with the smallest pore size. Static and dynamic tests were carried out using different strain rate: 1.4·10⁻³, 7·10⁻², 1.4·10⁻¹, and 3·10³ s⁻¹. Compressive strength, stress at plateau zone, and absorbed energy were determined. It was found that the ceramic-elastomer composites’ ability to absorb energy depended on the specific surface fraction of the interphase boundaries and achieved a value between 15.3 MJ/m³ in static test and 51.1 MJ/m³ for dynamic strain rate. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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20 pages, 8683 KiB

Open AccessArticle

Towards the Development of Novel Hybrid Composite Steel Pipes: Electrochemical Evaluation of Fiber-Reinforced Polymer Layered Steel against Corrosion

by Fatima Ghassan Alabtah, Elsadig Mahdi, Faysal Fayez Eliyan, Elsadig Eltai and Marwan Khraisheh

Polymers 2021, 13(21), 3805; https://doi.org/10.3390/polym13213805 - 3 Nov 2021

Cited by 4 | Viewed by 2751

Abstract

Corrosion remains one of the major and most costly challenges faced by the steel industry. Various fiber-reinforced polymer coating systems have been proposed to protect metallic piping distribution networks against corrosion. Despite increasing interest among scientific and industrial communities, there is only limited [...] Read more.

Corrosion remains one of the major and most costly challenges faced by the steel industry. Various fiber-reinforced polymer coating systems have been proposed to protect metallic piping distribution networks against corrosion. Despite increasing interest among scientific and industrial communities, there is only limited predictive capability for selecting the optimum composite system for a given corrosive condition. In this study, we present a comprehensive evaluation of the electrochemical behavior of two different fiber-reinforced polymer composite systems against the corrosion of carbon steel pipes under a wide range of acidic and corrosive solutions. The composites were made of glass and Kevlar fibers with an epoxy resin matrix and were subjected to corrosive solutions of 0.5 M NaCl, 0.5 M HCl, and 0.5 M H₂SO₄. The kinetics of the corrosion reactions were evaluated using potentiodynamic polarization (PDP) tests. In addition, electrochemical impedance spectroscopy (EIS) tests were carried out at open circuit potentials (OCPs). It was demonstrated that the glass fiber-reinforced polymer coating system offered the best protection against corrosion, with a high stability against deterioration when compared with epoxy and Kevlar fiber-reinforced polymer coating systems. Scanning electron microscopy images revealed cracks and deteriorated embedded fibers due to acid attack, sustained/assisted by the diffusion of the corrosion species. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 8265 KiB

Open AccessArticle

New Multicolor Tungstate-Molybdate Microphosphors as an Alternative to LED Components

by Justyna Czajka, Agata Szczeszak, Nina Kaczorowska and Stefan Lis

Materials 2021, 14(21), 6608; https://doi.org/10.3390/ma14216608 - 2 Nov 2021

Cited by 4 | Viewed by 1845

Abstract

Due to the ongoing need to create phosphors with the appropriate emission color for the production of light emitting diodes, we decided to synthesize a series of multicolour microphosphors with tunable visible emissions, depending on the composition of dopant ions. In this work, [...] Read more.

Due to the ongoing need to create phosphors with the appropriate emission color for the production of light emitting diodes, we decided to synthesize a series of multicolour microphosphors with tunable visible emissions, depending on the composition of dopant ions. In this work, we investigated the structure, morphology, and luminescent properties of new molybdate–tungstate phosphors co-doped with Tb³⁺ and Eu³⁺ ions. The conventional high temperature solid state method was used to prepare a series of CaMo_yW_1−yO₄:Eu³⁺_x/Tb³⁺_1−x materials. In order to obtain phosphors with the most promising luminescent properties, the experiment was planned by taking into account the different composition of the matrix and the concentration of the particular dopant ions (Eu³⁺_x/Tb³⁺_1−x, x = 0.001, 0.003, 0.005, 0.007, 0.009). As a result, luminescent materials were obtained with a pure tetragonal crystal structure, the space group of I4₁/a, confirmed by X-ray diffraction (XRD). The size and shape of the particles obtained from the materials were analyzed based on scanning electron microscopy images. Luminescence spectroscopy (excitation and emission spectra, decay lifetimes) was utilized to characterize the luminescence properties of the as-prepared phosphors. The color change of the emission from green-yellow to orange-red was confirmed using the 1931 Comission Internationale de l’Eclairage (CIE) chromaticity coordinates and color correlated temperature (CCT). Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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9 pages, 2077 KiB

Open AccessArticle

Changes of Crystal Structure and Microstructure of MoN Coatings in Accordance with Inductively Coupled Plasma Power

by Sung-Yong Chun

Coatings 2021, 11(11), 1351; https://doi.org/10.3390/coatings11111351 - 2 Nov 2021

Cited by 3 | Viewed by 1907

Abstract

Nano-crystalline MoN coatings were prepared by inductively coupled plasma magnetron sputtering (ICPMS) according to changing the plasma power from 0 to 200 W. The properties of the coatings were analyzed by X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, a nano-indentation [...] Read more.

Nano-crystalline MoN coatings were prepared by inductively coupled plasma magnetron sputtering (ICPMS) according to changing the plasma power from 0 to 200 W. The properties of the coatings were analyzed by X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, a nano-indentation tester, and a semiconductor characterization system. As the ICP power increased, the crystal structure of the MoN coatings was changed from a mixed phase of γ-Mo₂N and α-Mo to a single phase of γ-Mo₂N. The residual stress of the MoN coatings was also converted from tensile stress to compressive stress according to the increasing ICP power. As a result, the coatings deposited by the ICPMS have a very compact microstructure with high hardness: the nano-indentation hardness reached up to 27.1 GPa. The electrical resistivity of the coatings was decreased from 691.6 to 325.9 μΩ·cm as the ICP power increased as well. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 5823 KiB

Open AccessArticle

Effect of Annealing on Surface Morphology and Structure of Nickel Coatings Deposited from Deep Eutectic Solvents

by Juliusz Winiarski, Anna Niciejewska, Włodzimierz Tylus, Katarzyna Winiarska, Karolina Pazgan and Bogdan Szczygieł

Coatings 2021, 11(11), 1347; https://doi.org/10.3390/coatings11111347 - 2 Nov 2021

Cited by 4 | Viewed by 2225

Abstract

Nanocrystalline nickel coatings deposited on a copper base material from DES made of choline chloride and ethylene glycol in 1:2 molar ratio containing 1 mol dm⁻³ NiCl₂⋅6H₂O were modified through post-deposition heat treatment at the temperatures from 100 [...] Read more.

Nanocrystalline nickel coatings deposited on a copper base material from DES made of choline chloride and ethylene glycol in 1:2 molar ratio containing 1 mol dm⁻³ NiCl₂⋅6H₂O were modified through post-deposition heat treatment at the temperatures from 100 to 400 °C. As-deposited coatings were composed of spheroidal agglomerates with the size of several hundred nanometers interspersed with lamellar crystals, but after annealing at 300 °C and 400 °C only single nano-sized plates embedded in a granular and porous layer remained. As the temperature of the heat treatment increased from 100 °C to 400 °C, the mean crystallite size increased from 13 to 35 nm. The change in crystallite size was accompanied by a change in microhardness, the maximum value of which was measured for the annealed coating at 200 °C. As a result of heat treatment, coatings were gradually covered by a layer of oxidized nickel species. XPS analyses showed that NiOOH and Ni(OH)₂ dominated among them. Above 200 °C the share of these compounds began to decline in the face of the increasing share of NiO. This, in turn, clearly translated into a deterioration of the corrosion resistance of Ni coatings annealed at 300 °C, and especially at 400 °C, during exposure in 0.05 mol dm⁻³ NaCl solution. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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15 pages, 3410 KiB

Open AccessArticle

Physical Mechanisms of Magnetic Field Effects on the Dielectric Function of Hybrid Magnetorheological Suspensions

by Gabriela-Eugenia Iacobescu, Ioan Bica and Larisa-Marina-Elisabeth Chirigiu

Materials 2021, 14(21), 6498; https://doi.org/10.3390/ma14216498 - 29 Oct 2021

Cited by 5 | Viewed by 1640

Abstract

In this paper, we study the electrical properties of new hybrid magnetorheological suspensions (hMRSs) and propose a theoretical model to explain the dependence of the electric capacitance on the iron volumetric fraction,

Φ_{F e}

, of the dopants and on the external [...] Read more.

In this paper, we study the electrical properties of new hybrid magnetorheological suspensions (hMRSs) and propose a theoretical model to explain the dependence of the electric capacitance on the iron volumetric fraction,

Φ_{F e}

, of the dopants and on the external magnetic field. The hMRSs, with dimensions of

30 mm \times 30 mm \times 2 mm,

were manufactured based on impregnating cotton fabric, during heating, with three solutions of iron microparticles in silicone oil. Flat capacitors based on these hMRSs were then produced. The time variation of the electric capacitance of the capacitors was measured in the presence and absence of a magnetic field,

B

, in a time interval of 300 s, with

Δ t = 1 s

steps. It was shown that for specific values of

Φ_{F e}

and

B

, the coupling coefficient between the cotton fibers and the magnetic dipoles had values corresponding to very stable electrical capacitance. Using magnetic dipole approximation, the mechanisms underlying the observed phenomena can be described if the hMRSs are considered continuous media. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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22 pages, 386 KiB

Open AccessReview

Biotechnological Applications of Polymeric Nanofiber Platforms Loaded with Diverse Bioactive Materials

by M. R. El-Aassar, Omar M. Ibrahim and Ziad H. Al-Oanzi

Polymers 2021, 13(21), 3734; https://doi.org/10.3390/polym13213734 - 28 Oct 2021

Cited by 19 | Viewed by 3571

Abstract

This review article highlights the critical research and formative works relating to nanofiber composites loaded with bioactive materials for diverse applications, and discusses the recent research on the use of electrospun nanofiber incorporating bioactive compounds such as essential oils, herbal bioactive components, plant [...] Read more.

This review article highlights the critical research and formative works relating to nanofiber composites loaded with bioactive materials for diverse applications, and discusses the recent research on the use of electrospun nanofiber incorporating bioactive compounds such as essential oils, herbal bioactive components, plant extracts, and metallic nanoparticles. Inevitably, with the common advantages of bioactive components and polymer nanofibers, electrospun nanofibers containing bioactive components have attracted intense interests for their applications in biomedicine and cancer treatment. Many studies have only concentrated on the production and performance of electrospun nanofiber loaded with bioactive components; in this regard, the features of different types of electrospun nanofiber incorporating a wide variety of bioactive compounds and their developing trends are summarized and assessed in the present article, as is the feasible use of nanofiber technology to produce products on an industrial scale in different applications. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

11 pages, 5072 KiB

Open AccessArticle

Performance Comparison of Geodrain Drainage and Gravel Drainage Layers Embedded in a Horizontal Plane

by Mariusz Cholewa and Karol Plesiński

Materials 2021, 14(21), 6321; https://doi.org/10.3390/ma14216321 - 22 Oct 2021

Viewed by 1792

Abstract

Drainage materials are widely used, among other uses, in the construction of landfills. Regulations require a drainage layer in the base and a covering for the landfill. The implementation of a gravel drain requires a lot of material and financial outlays. New geocomposite [...] Read more.

Drainage materials are widely used, among other uses, in the construction of landfills. Regulations require a drainage layer in the base and a covering for the landfill. The implementation of a gravel drain requires a lot of material and financial outlays. New geocomposite materials are an alternative, and facilitate construction. The aim of the research was to compare the drainage properties of the Pozidrain 7S250D/NW8 geocomposite and gravel drainage. The model test was performed on a specially prepared test stand. The research was carried out for model #1, in which the gravel drainage was built. Model #2 had a drainage geocomposite built into it. The test results show the values of the volumetric flow rate for geodrains, with a maximum value of 40 dm³·min⁻¹. For the gravel layer, values of up to 140 dm³·min⁻¹ were recorded. Another parameter recorded during the damming of water by the embankment was the speed of water suction by the geosynthetic and gravel drainage; the values were 0.067 and 0.024 m³·s⁻¹, respectively. The efficiency of water drainage through the geocomposite was sufficient. It is possible to use the slopes of the landfill for drainage, which will reduce material and financial outlays. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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15 pages, 4361 KiB

Open AccessArticle

New Copper Alloys Used to Make Products Intended for Contact with Drinking Water

by Michał Chruściński, Szymon Szkudelski, Jacek Borowski, Artur Meller and Marcin Suszyński

Materials 2021, 14(21), 6301; https://doi.org/10.3390/ma14216301 - 22 Oct 2021

Cited by 2 | Viewed by 2478

Abstract

This article presents the results of tests conducted as part of a research project with the primary objective of developing new copper alloys with limited lead content. The new group of materials were created in a production plant. As part of tests, a [...] Read more.

This article presents the results of tests conducted as part of a research project with the primary objective of developing new copper alloys with limited lead content. The new group of materials were created in a production plant. As part of tests, a group of 22 alloys were selected for testing in castability, structural characteristics and hardness. Based on the test results obtained, the group of alloys under study was narrowed down to nine. The mechanical properties of these alloys were determined in static tensile tests as well as in uniaxial upsetting tests at elevated temperature, on the basis of which the group of alloys under investigation was further narrowed to three. Further studies involved technological verification of the application of these alloys under industrial conditions. These alloys were subject to numerical forging analyses, along with forging tests, under semi-industrial conditions, where the degree of filling of a die impression at a specific temperature was measured using an optic scanner. The quality of production of the obtained forgings was evaluated macroscopically with simultaneous observations of the microstructure. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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15 pages, 1089 KiB

Open AccessReview

Shielding of Cosmic Radiation by Fibrous Materials

by Tomasz Blachowicz and Andrea Ehrmann

Fibers 2021, 9(10), 60; https://doi.org/10.3390/fib9100060 - 15 Oct 2021

Cited by 16 | Viewed by 12194

Abstract

Cosmic radiation belongs to the challenges engineers have to deal with when further developing space travel. Besides the severe risks for humans due to high-energy particles or waves, the impact of cosmic radiation on electronics and diverse materials cannot be neglected, even in [...] Read more.

Cosmic radiation belongs to the challenges engineers have to deal with when further developing space travel. Besides the severe risks for humans due to high-energy particles or waves, the impact of cosmic radiation on electronics and diverse materials cannot be neglected, even in microsatellites or other unmanned spacecraft. Here, we explain the different particles or waves found in cosmic radiation and their potential impact on biological and inanimate matter. We give an overview of fiber-based shielding materials, mostly applied in the form of composites, and explain why these materials can help shielding spaceships or satellites from cosmic radiation. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 4568 KiB

Open AccessArticle

Preparation of Degradable Superhydrophobic Mg/P/Z/F/H Composite Materials and Their Anticorrosion

by Zhongxian Xi, Chengqing Yuan, Xiuqin Bai, Chun Wang and Anne Neville

Coatings 2021, 11(10), 1239; https://doi.org/10.3390/coatings11101239 - 12 Oct 2021

Cited by 1 | Viewed by 2218

Abstract

In this study, the degradable superhydrophobic Mg/P/Z/F/H (magnesium/poly(-caprolactone)/zinc oxide/1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES)/heating process) composite materials were prepared through dip-coating method and heating process, for enhancing the corrosion resistance of the AZ91D magnesium alloys. The electrochemical measurements revealed that the Mg/P/Z/F/H materials significantly improved the corrosion [...] Read more.

In this study, the degradable superhydrophobic Mg/P/Z/F/H (magnesium/poly(-caprolactone)/zinc oxide/1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES)/heating process) composite materials were prepared through dip-coating method and heating process, for enhancing the corrosion resistance of the AZ91D magnesium alloys. The electrochemical measurements revealed that the Mg/P/Z/F/H materials significantly improved the corrosion resistance of the magnesium alloys in 3.5 wt.% NaCl. The Mg/P/Z/F/H composite materials exhibited efficient self-cleaning properties, good adhesion strength, and stability in wet atmosphere. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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20 pages, 4206 KiB

Open AccessArticle

Sustainable Chitosan-Dialdehyde Cellulose Nanocrystal Film

by Cong Gao, Shuo Wang, Baojie Liu, Shuangquan Yao, Yi Dai, Long Zhou, Chengrong Qin and Pedram Fatehi

Materials 2021, 14(19), 5851; https://doi.org/10.3390/ma14195851 - 6 Oct 2021

Cited by 24 | Viewed by 3594

Abstract

In this study, we incorporated 2,3-dialdehyde nanocrystalline cellulose (DANC) into chitosan as a reinforcing agent and manufactured biodegradable films with enhanced gas barrier properties. DANC generated via periodate oxidation of cellulose nanocrystal (CNC) was blended at various concentrations with chitosan, and bionanocomposite films [...] Read more.

In this study, we incorporated 2,3-dialdehyde nanocrystalline cellulose (DANC) into chitosan as a reinforcing agent and manufactured biodegradable films with enhanced gas barrier properties. DANC generated via periodate oxidation of cellulose nanocrystal (CNC) was blended at various concentrations with chitosan, and bionanocomposite films were prepared via casting and characterized systematically. The results showed that DANC developed Schiff based bond with chitosan that improved its properties significantly. The addition of DANC dramatically improved the gas barrier performance of the composite film, with water vapor permeability (WVP) value decreasing from 62.94 g·mm·m⁻²·atm⁻¹·day⁻¹ to 27.97 g·mm·m⁻²·atm⁻¹·day⁻¹ and oxygen permeability (OP) value decreasing from 0.14 cm³·mm·m⁻²·day⁻¹·atm⁻¹ to 0.026 cm³·mm·m⁻²·day⁻¹·atm⁻¹. Meanwhile, the maximum decomposition temperature (Td_max) of the film increased from 286 °C to 354 °C, and the tensile strength of the film was increased from 23.60 MPa to 41.12 MPa when incorporating 25 wt.% of DANC. In addition, the chitosan/DANC (75/25, wt/wt) films exhibited superior thermal stability, gas barrier, and mechanical strength compared to the chitosan/CNC (75/25, wt/wt) film. These results confirm that the DANC and chitosan induced films with improved gas barrier, mechanical, and thermal properties for possible use in film packaging. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 24276 KiB

Open AccessArticle

Encapsulation of Cochleates Derived from Salmonella Infantis with Biopolymers to Develop a Potential Oral Poultry Vaccine

by Constanza Avendaño, Sonia Vidal, María Gabriela Villamizar-Sarmiento, Miguel Guzmán, Héctor Hidalgo, Lisette Lapierre, Carolina Valenzuela and Leonardo Sáenz

Polymers 2021, 13(19), 3426; https://doi.org/10.3390/polym13193426 - 6 Oct 2021

Cited by 2 | Viewed by 2192

Abstract

The aim of this study was to develop and characterize Salmonellaenterica serovar Infantis (S. Infantis) cochleates protected by encapsulation technology as a potential vaccine and to determine its safety in pullets. Cochleates were encapsulated by two technologies, spray drying and ionotropic [...] Read more.

The aim of this study was to develop and characterize Salmonellaenterica serovar Infantis (S. Infantis) cochleates protected by encapsulation technology as a potential vaccine and to determine its safety in pullets. Cochleates were encapsulated by two technologies, spray drying and ionotropic gelation at different concentrations (0–15% v/v), and were characterized by physicochemical properties, protein content and Fourier Transform Infrared Spectroscopy (FTIR). The cochleates were white liquid suspensions with tubular shapes and a protein content of 1.0–2.1 mg/mL. After encapsulation by spray drying, microparticles ranged in size from 10.4–16.9 µm, were spherical in shape, and the protein content was 0.7–1.8 mg/g. After encapsulation by ionotropic gelation, beads ranged in size from 1620–1950 µm and were spherical in shape with a protein content of 1.0–2.5 mg/g. FTIR analysis indicated that both encapsulation processes were efficient. The cochleates encapsulated by ionotropic gelation were then tested for safety in pullets. No ill effect on the health of animals was observed upon physical or postmortem examination. In conclusion, this study was the first step in developing a potential oral S. Infantis vaccine safe for poultry using a novel cochleate encapsulation technology. Future studies are needed to determine the effectiveness of the vaccine. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 314 KiB

Open AccessReview

Antimicrobial Peptides-Coated Stainless Steel for Fighting Biofilms Formation for Food and Medical Fields: Review of Literature

by Mayssane Hage, Hikmat Akoum, Nour-Eddine Chihib and Charafeddine Jama

Coatings 2021, 11(10), 1216; https://doi.org/10.3390/coatings11101216 - 4 Oct 2021

Cited by 7 | Viewed by 3121

Abstract

Emerging technology regarding antimicrobial coatings contributes to fighting the challenge of pathogenic bacterial biofilms in medical and agri-food environments. Stainless steel is a material widely used in those fields since it has satisfying mechanical properties, but it, unfortunately, lacks the required bio-functionality, rendering [...] Read more.

Emerging technology regarding antimicrobial coatings contributes to fighting the challenge of pathogenic bacterial biofilms in medical and agri-food environments. Stainless steel is a material widely used in those fields since it has satisfying mechanical properties, but it, unfortunately, lacks the required bio-functionality, rendering it vulnerable to bacterial adhesion and biofilm formation. Therefore, this review aims to present the coatings developed by employing biocides grafted on stainless steel. It also highlights antimicrobial peptides (AMPs)used to coat stainless steel, particularly nisin, which is commonly accepted as a safe alternative to prevent pathogenic biofilm development. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 4819 KiB

Open AccessArticle

Prediction of Geopolymer Concrete Compressive Strength Using Novel Machine Learning Algorithms

by Ayaz Ahmad, Waqas Ahmad, Krisada Chaiyasarn, Krzysztof Adam Ostrowski, Fahid Aslam, Paulina Zajdel and Panuwat Joyklad

Polymers 2021, 13(19), 3389; https://doi.org/10.3390/polym13193389 - 2 Oct 2021

Cited by 58 | Viewed by 5190

Abstract

The innovation of geopolymer concrete (GPC) plays a vital role not only in reducing the environmental threat but also as an exceptional material for sustainable development. The application of supervised machine learning (ML) algorithms to forecast the mechanical properties of concrete also has [...] Read more.

The innovation of geopolymer concrete (GPC) plays a vital role not only in reducing the environmental threat but also as an exceptional material for sustainable development. The application of supervised machine learning (ML) algorithms to forecast the mechanical properties of concrete also has a significant role in developing the innovative environment in the field of civil engineering. This study was based on the use of the artificial neural network (ANN), boosting, and AdaBoost ML approaches, based on the python coding to predict the compressive strength (CS) of high calcium fly-ash-based GPC. The performance comparison of both the employed techniques in terms of prediction reveals that the ensemble ML approaches, AdaBoost, and boosting were more effective than the individual ML technique (ANN). The boosting indicates the highest value of R² equals 0.96, and AdaBoost gives 0.93, while the ANN model was less accurate, indicating the coefficient of determination value equals 0.87. The lesser values of the errors, MAE, MSE, and RMSE of the boosting technique give 1.69 MPa, 4.16 MPa, and 2.04 MPa, respectively, indicating the high accuracy of the boosting algorithm. However, the statistical check of the errors (MAE, MSE, RMSE) and k-fold cross-validation method confirms the high precision of the boosting technique. In addition, the sensitivity analysis was also introduced to evaluate the contribution level of the input parameters towards the prediction of CS of GPC. The better accuracy can be achieved by incorporating other ensemble ML techniques such as AdaBoost, bagging, and gradient boosting. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 4902 KiB

Open AccessArticle

Development and Characterization of Lightweight Geopolymer Composite Reinforced with Hybrid Carbon and Steel Fibers

by Agnieszka Baziak, Kinga Pławecka, Izabela Hager, Arnaud Castel and Kinga Korniejenko

Materials 2021, 14(19), 5741; https://doi.org/10.3390/ma14195741 - 1 Oct 2021

Cited by 15 | Viewed by 2527

Abstract

The aim of this paper is to analyze the influence of hybrid fiber reinforcement on the properties of a lightweight fly ash-based geopolymer. The matrix includes the ratio of fly ash and microspheres at 1:1. Carbon and steel fibers have been chosen due [...] Read more.

The aim of this paper is to analyze the influence of hybrid fiber reinforcement on the properties of a lightweight fly ash-based geopolymer. The matrix includes the ratio of fly ash and microspheres at 1:1. Carbon and steel fibers have been chosen due to their high mechanical properties as reinforcement. Short steel fibers (SFs) and/or carbon fibers (CFs) were used as reinforcement in the following proportions: 2.0% wt. CFs, 1.5% wt. CFs and 0.5% wt. SFs, 1.0% wt. CFs and 1.0% wt. SFs, 0.5% wt. CFs and 1.5% wt. SFs and 2.0% wt. SFs. Hybrid reinforcement of geopolymer composites was used to obtain optimal strength properties, i.e., compressive strength due to steel fiber and bending strength due to carbon fibers. Additionally, reference samples consisting of the geopolymer matrix material itself. After the production of geopolymer composites, their density was examined, and the structure (using scanning electron microscopy) and mechanical properties (i.e., bending and compressive strength) in relation to the type and amount of reinforcement. In addition, to determine the thermal insulation properties of the geopolymer matrix, its thermal conductivity coefficient was determined. The results show that the addition of fiber improved compressive and bending strength. The best compressive strength is obtained for a steel fiber-reinforced composite (2.0% wt.). The best bending strength is obtained for the hybrid reinforced composite: 1.5% wt. CFs and 0.5% wt. SFs. The geopolymer composite is characterized by low thermal conductivity (0.18–0.22 W/m ∙ K) at low density (0.89–0.93 g/cm³). Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 6463 KiB

Open AccessArticle

Formation and Growth of Intermetallic Compounds during Reactions between Liquid Gallium and Solid Nickel

by Doyoung Lee, Chang-Lae Kim and Yoonchul Sohn

Materials 2021, 14(19), 5694; https://doi.org/10.3390/ma14195694 - 30 Sep 2021

Cited by 6 | Viewed by 2655

Abstract

Liquid metals, such as Ga and eutectic Ga-In, have been extensively studied for various applications, including flexible and wearable devices. For applying liquid metal to electronic devices, interconnection with the various metal electrodes currently in use, and verifying their mechanical reliability are essential. [...] Read more.

Liquid metals, such as Ga and eutectic Ga-In, have been extensively studied for various applications, including flexible and wearable devices. For applying liquid metal to electronic devices, interconnection with the various metal electrodes currently in use, and verifying their mechanical reliability are essential. Here, detailed investigations of the formation and growth of intermetallic compounds (IMCs) during the reactions between liquid Ga and solid nickel were conducted. Ga and Ni were reacted at 250, 300, and 350 °C for 10–240 min. The IMC double layer observed after the reactions contained a Ga₇Ni₃ bottom layer formed during the reactions, and a Ga_xNi top layer (with 89–95 at.% of Ga) precipitated during cooling. Numerous empty channels exist between the rod-type Ga₇Ni₃ IMCs. Ga₇Ni₃ growth occurred only in the vertical direction, without lateral coarsening and merging between the rods. The time exponents were measured at 1.1–1.5, implying that the reaction kinetics were near-interface reaction-controlled. The activation energy for Ga₇Ni₃ growth was determined as 49.1 kJ/mol. The experimental results of the Ga-Ni reaction study are expected to provide important information for incorporating liquid metals into electronic devices in the future. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 4800 KiB

Open AccessArticle

Role of Mg(NO₃)₂ as Defective Agent in Ameliorating the Electrical Conductivity, Structural and Electrochemical Properties of Agarose–Based Polymer Electrolytes

by N. I. Ali, S. Z. Z. Abidin, S. R. Majid and N. K. Jaafar

Polymers 2021, 13(19), 3357; https://doi.org/10.3390/polym13193357 - 30 Sep 2021

Cited by 4 | Viewed by 2220

Abstract

Polymer electrolytes based on agarose dissolved in DMSO solvent complexed with different weight percentages of Mg(NO₃)₂ ranging from 0 to 35 wt% were prepared using a solution casting method. Electrochemical impedance spectroscopy (EIS) was applied to study the electrical properties [...] Read more.

Polymer electrolytes based on agarose dissolved in DMSO solvent complexed with different weight percentages of Mg(NO₃)₂ ranging from 0 to 35 wt% were prepared using a solution casting method. Electrochemical impedance spectroscopy (EIS) was applied to study the electrical properties of this polymer electrolyte, such as ionic conductivity at room and different temperatures, dielectric and modulus properties. The highest conducting film has been obtained at 1.48 × 10⁻⁵ S·cm⁻¹ by doping 30 wt% of Mg(NO₃)₂ into the polymer matrix at room temperature. This high ionic conductivity value is achieved due to the increase in the amorphous nature of the polymer electrolyte, as proven by X-ray diffractometry (XRD), where broadening of the amorphous peak can be observed. The intermolecular interactions between agarose and Mg(NO₃)₂ are studied by Fourier transform infrared (FTIR) spectroscopy by observing the presence of –OH, –CH, N–H, CH₃, C–O–C, C–OH, C–C and 3,6-anhydrogalactose bridges in the FTIR spectra. The electrochemical properties for the highest conducting agarose–Mg(NO₃)₂ polymer electrolyte are stable up to 3.57 V, which is determined by using linear sweep voltammetry (LSV) and supported by cyclic voltammetry (CV) that proves the presence of Mg²⁺ conduction. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 3870 KiB

Open AccessArticle

Characterization and Anticancer Activity of Biosynthesized Au/Cellulose Nanocomposite from Chlorella vulgaris

by Ragaa A. Hamouda, Ahmed I. Abd El Maksoud, Madonna Wageed, Amenah S. Alotaibi, Dalia Elebeedy, Hany Khalil, Amr Hassan and Asmaa Abdella

Polymers 2021, 13(19), 3340; https://doi.org/10.3390/polym13193340 - 29 Sep 2021

Cited by 25 | Viewed by 3420

Abstract

Therapeutic selectivity is a critical issue in cancer therapy. As a result of its adjustable physicochemical characteristics, the Au/cellulose nanocomposite currently holds a lot of potential for solving this challenge. This work was designed to prepare a Au/cellulose nanocomposite with enhanced anticancer activity [...] Read more.

Therapeutic selectivity is a critical issue in cancer therapy. As a result of its adjustable physicochemical characteristics, the Au/cellulose nanocomposite currently holds a lot of potential for solving this challenge. This work was designed to prepare a Au/cellulose nanocomposite with enhanced anticancer activity through the regulation of the mitogen-activated protein kinases (MAPK) signaling pathway. Nanocellulose, nanogold (AuNPs), and a Au/cellulose nanocomposite were biosynthesized from microgreen alga Chlorella vulgaris. Using UV-Vis absorption spectroscopy, transmission electron microscope (TEM), zeta potential analyzer, and Fourier transform infrared spectroscopy (FTIR), the synthesized nanoparticles were confirmed and characterized. In human alveolar basal epithelial cells (A549 cells), the selectivity and anticancer activity of the produced nanoparticles were evaluated. The cytotoxicity results revealed that the inhibitory concentration (IC50) of the Au/cellulose nanocomposite against A549 cancer lung cells was 4.67 ± 0.17 µg/µL compared to 182.75 ± 6.45 µg/µL in the case of HEL299 normal lung fibroblasts. It was found that treatment with nanocellulose and the Au/cellulose nanocomposite significantly increased (p < 0.05) the relative expression of tumor suppressor 53 (p53) in comparison to control cells. They also significantly (p < 0.05) decreased the relative expression of the Raf-1 gene. These findings indicate that nanocellulose and the Au/cellulose nanocomposite regulate cell cycles mostly via the motivation of p53 gene expression and reduction of Raf-1 gene expression. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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10 pages, 2045 KiB

Open AccessCommunication

Hyaluronic Acid-Based Gold Nanoparticles for the Topical Delivery of Therapeutics to the Retina and the Retinal Pigment Epithelium

by Amine Laradji, Bedia B. Karakocak, Alexander V. Kolesnikov, Vladimir J. Kefalov and Nathan Ravi

Polymers 2021, 13(19), 3324; https://doi.org/10.3390/polym13193324 - 28 Sep 2021

Cited by 13 | Viewed by 2798

Abstract

The ocular immune privilege is a phenomenon brought about by anatomical and physiological barriers to shield the eye from immune and inflammation responses. While this phenomenon is beneficial for eyes protection, it is, at the same time, a hindrance for drug delivery to [...] Read more.

The ocular immune privilege is a phenomenon brought about by anatomical and physiological barriers to shield the eye from immune and inflammation responses. While this phenomenon is beneficial for eyes protection, it is, at the same time, a hindrance for drug delivery to the posterior segment of the eye to treat retinal diseases. Some ocular barriers can be bypassed by intravitreal injections, but these are associated with several side effects and patient noncompliance, especially when frequent injections are required. As an alternative, applying drugs as an eye drop is preferred due to the safety and ease. This study investigated the possible use of topically-applied hyaluronic acid-coated gold nanoparticles as drug delivery vehicles to the back of the eye. The coated gold nanoparticles were topically applied to mouse eyes, and results were compared to topically applied uncoated gold nanoparticles and phosphate-buffered saline (PBS) solution. Retina sections from these mice were then analyzed using fluorescence microscopy, inductively coupled plasma mass spectrometry (ICP-MS), and transmission electron microscopy (TEM). All characterization techniques used in this study suggest that hyaluronic acid-coated gold nanoparticles have higher distribution in the posterior segment of the eye than uncoated gold nanoparticles. Electroretinogram (ERG) analysis revealed that the visual function of mice receiving the coated gold nanoparticles was not affected, and these nanoparticles can, therefore, be applied safely. Together, our results suggest that hyaluronic acid-coated gold nanoparticles constitute potential drug delivery vehicles to the retina when applied noninvasively as an eye drop. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 4530 KiB

Open AccessArticle

Peptide Conjugate on Multilayer Graphene Oxide Film for the Osteogenic Differentiation of Human Wharton’s Jelly-Derived Mesenchymal Stem Cells

by Perng Yang Puah, Pak Yan Moh, Coswald Stephen Sipaut, Ping Chin Lee and Siew Eng How

Polymers 2021, 13(19), 3290; https://doi.org/10.3390/polym13193290 - 26 Sep 2021

Cited by 7 | Viewed by 2741

Abstract

Graphene oxide (GO) is extensively studied as a template material for mesenchymal stem cell application due to its two-dimensional nature and unique functionalization chemistries. Herein, a new type of peptide-conjugated multilayer graphene oxide (peptide/m-GO film) was fabricated and used as biomaterial for culturing [...] Read more.

Graphene oxide (GO) is extensively studied as a template material for mesenchymal stem cell application due to its two-dimensional nature and unique functionalization chemistries. Herein, a new type of peptide-conjugated multilayer graphene oxide (peptide/m-GO film) was fabricated and used as biomaterial for culturing human Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs). The characterization of the peptide/m-GO films was performed, and the biocompatibility of the WJ-MSCs on the peptide/m-GO films was investigated. The results demonstrated that the peptide conjugate on the m-GO film did not hamper the normal growth of WJ-MSCs but supported the growth of WJ-MSCs after the 6-day culture period. In addition, the osteogenic differentiation of WJ-MSCs on the peptide/m-GO films was enhanced as compared with the parent m-GO film. Therefore, such peptide-conjugated m-GO films could provide a highly biocompatible and multifunctional 2D material to tailor the potential application of WJ-MSCs in bone tissue regeneration. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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10 pages, 16330 KiB

Open AccessArticle

Microstructure Characterization of Ni-Based Alloys for Packaging Application upon Long-Term Heat Treatment

by Jianbing Ren, Yilong Ma and Kejian Li

Coatings 2021, 11(10), 1159; https://doi.org/10.3390/coatings11101159 - 26 Sep 2021

Cited by 1 | Viewed by 1731

Abstract

In this study, an investigation was conducted to examine two types of Ni-based alloys upon long-term heat treatment and compare their grains, surface corrosion layers and microhardness values. The working environment of the tested samples was a temperature of 1000 °C for 5000 [...] Read more.

In this study, an investigation was conducted to examine two types of Ni-based alloys upon long-term heat treatment and compare their grains, surface corrosion layers and microhardness values. The working environment of the tested samples was a temperature of 1000 °C for 5000 h. Two samples, respectively, contained low (~8 wt.%) and high (~16 wt.%) contents of Mo, and the low-Mo-content sample contained Nb (~4 wt.%) and other elements. The grains, precipitates, corrosion layers and microhardness values of the samples before and after heat treatment were determined by scanning electron microscopy, electron back-scattered diffraction, transmission electron microscopy, X-ray diffraction analysis and Vickers hardness tests. The results revealed that the grain was surprisingly stable in the sample with the higher Mo content; after heat treatment, the grain size was ~35 μm, which was similar to the grain size before heat treatment. Moreover, for the sample with the higher Mo content, the microhardness was found to be higher, especially after long-term high-temperature treatment, which is of great significance for the long service life of materials. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 4923 KiB

Open AccessArticle

The Application of Hollow Carbon Nanofibers Prepared by Electrospinning to Carbon Dioxide Capture

by Yu-Chun Chiang, Wei-Ting Chin and Chih-Cheng Huang

Polymers 2021, 13(19), 3275; https://doi.org/10.3390/polym13193275 - 25 Sep 2021

Cited by 10 | Viewed by 3083

Abstract

Coaxial electrospinning has been considered a straightforward and convenient method for producing hollow nanofibers. Therefore, the objective of this study was to develop hollow activated carbon nanofibers (HACNFs) for CO₂ capture in order to reduce emissions of CO₂ to the atmosphere [...] Read more.

Coaxial electrospinning has been considered a straightforward and convenient method for producing hollow nanofibers. Therefore, the objective of this study was to develop hollow activated carbon nanofibers (HACNFs) for CO₂ capture in order to reduce emissions of CO₂ to the atmosphere and mitigate global warming. Results showed that the sacrificing core could be decomposed at carbonization temperatures above 900 °C, allowing the formation of hollow nanofibers. The average outer diameters of HACNFs ranged from 550 to 750 nm, with a shell thickness of 75 nm. During the carbonization stage, the denitrogenation reactions were significant, while in the CO₂ activation process, the release of carbon oxides became prominent. Therefore, the CO₂ activation could increase the percentages of N=C and quaternary N groups. The major nitrogen functionalities on most samples were O=C–NH and quaternary N. However, =C and quaternary N groups were found to be crucial in determining the CO₂ adsorption performance. CO₂ adsorption on HACNFs occurred due to physical adsorption and was an exothermic reaction. The optimal CO₂ adsorption performance was observed for HACNFs carbonized at 900 °C, where 3.03 mmol/g (1 atm) and 0.99 mmol/g (0.15 atm) were measured at 25 °C. The degradation of CO₂ uptakes after 10 adsorption−desorption cyclic runs could be maintained within 8.9%. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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38 pages, 9099 KiB

Open AccessReview

Polysaccharide-Based Nanocomposites for Food Packaging Applications

by Kunal Pal, Preetam Sarkar, Arfat Anis, Karolina Wiszumirska and Maciej Jarzębski

Materials 2021, 14(19), 5549; https://doi.org/10.3390/ma14195549 - 24 Sep 2021

Cited by 23 | Viewed by 3832

Abstract

The article presents a review of the literature on the use of polysaccharide bionanocomposites in the context of their potential use as food packaging materials. Composites of this type consist of at least two phases, of which the outer phase is a polysaccharide, [...] Read more.

The article presents a review of the literature on the use of polysaccharide bionanocomposites in the context of their potential use as food packaging materials. Composites of this type consist of at least two phases, of which the outer phase is a polysaccharide, and the inner phase (dispersed phase) is an enhancing agent with a particle size of 1–100 nm in at least one dimension. The literature review was carried out using data from the Web of Science database using VosViewer, free software for scientometric analysis. Source analysis concluded that polysaccharides such as chitosan, cellulose, and starch are widely used in food packaging applications, as are reinforcing agents such as silver nanoparticles and cellulose nanostructures (e.g., cellulose nanocrystals and nanocellulose). The addition of reinforcing agents improves the thermal and mechanical stability of the polysaccharide films and nanocomposites. Here we highlighted the nanocomposites containing silver nanoparticles, which exhibited antimicrobial properties. Finally, it can be concluded that polysaccharide-based nanocomposites have sufficient properties to be tested as food packaging materials in a wide spectrum of applications. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 2101 KiB

Open AccessArticle

Electrospun Nanofibre Filtration Media to Protect against Biological or Nonbiological Airborne Particles

by Fabrice N. H. Karabulut, Günther Höfler, Naveen Ashok Chand and Gareth W. Beckermann

Polymers 2021, 13(19), 3257; https://doi.org/10.3390/polym13193257 - 24 Sep 2021

Cited by 18 | Viewed by 3819

Abstract

Electrospun nanofibres can outperform their melt-blown counterparts in many applications, especially air filtration. The different filtration mechanisms of nanofibres are particularly important when it comes to the air filtration of viruses (such as COVID-19) and bacteria. In this work, we present an electrospun [...] Read more.

Electrospun nanofibres can outperform their melt-blown counterparts in many applications, especially air filtration. The different filtration mechanisms of nanofibres are particularly important when it comes to the air filtration of viruses (such as COVID-19) and bacteria. In this work, we present an electrospun nanofibre filter media, FilterLayr^TM by NanoLayr Ltd., containing poly(methyl methacrylate)/ethylene vinyl alcohol nanofibres. The outstanding uniformity of the nanofibres was indicated by the good correlation between pressure drop (ΔP) and areal weight with R2 values in the range of 0.82 to 0.98 across various test air velocities. By adjusting the nanofibre areal weight (basis weight), the nanofibre filter media was shown to meet the particle filtration efficiency and breathability requirements of the following internationally accepted facemask and respirator standards: N95 respirator facemask performance in accordance with NIOSH 42CFR84 (filtration efficiency of up to 98.10% at a pressure drop of 226 Pa and 290 Pa at 85 L·min⁻¹ and 120 L·min⁻¹, respectively), Level 2 surgical facemask performance in accordance with ASTM F2299 (filtration efficiency of up to 99.97% at 100 nm particle size and a pressure drop of 44 Pa at 8 L·min⁻¹), and Level 2 filtration efficiency and Level 1 breathability for barrier face coverings in accordance with ASTM F3502 (filtration efficiency of up to 99.68% and a pressure drop of 133 Pa at 60 L·min⁻¹), with Level 2 breathability being achievable at lower nanofibre areal weights. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 5296 KiB

Open AccessArticle

Hopping Conductivity and Dielectric Relaxations in Ag/PAN Nanocomposites

by M.A. Kudryashov, A.A. Logunov, L.A. Mochalov, Yu.P. Kudryashova, M.M. Trubyanov, A.V. Barykin and I.V. Vorotyntsev

Polymers 2021, 13(19), 3251; https://doi.org/10.3390/polym13193251 - 24 Sep 2021

Cited by 2 | Viewed by 2099

Abstract

The dependence of the conductivity and electric modulus of silver/polyacrylonitrile nanocomposites on the frequency of an alternating electric field has been studied at different temperatures and starting mixture AgNO₃ contents. The frequency dependences on the conductivity of the nanocomposites in the range [...] Read more.

The dependence of the conductivity and electric modulus of silver/polyacrylonitrile nanocomposites on the frequency of an alternating electric field has been studied at different temperatures and starting mixture AgNO₃ contents. The frequency dependences on the conductivity of the nanocomposites in the range of 10³–10⁶ Hz are in good agreement with the power law f^0.8. The observed relaxation maxima in the relation of the imaginary part of the electric modulus on the frequency can be explained by interfacial polarization. It was shown that the frequency dispersions of conductivity and electric modulus were well described by the Dyre and Cole-Davidson models, respectively. Using these models, we have estimated the relaxation times and the activation energies of these structures. A mechanism of charge transport responsible for the conductivity of nanocomposites is proposed. An assumption is made regarding the presence of Ag₄²⁺ and Ag₈²⁺ silver clusters in the polymer. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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30 pages, 14190 KiB

Open AccessArticle

Research on Flashover Prediction Method of Large-Space Timber Structures in a Fire

by Yongwang Zhang and Lu Wang

Materials 2021, 14(19), 5515; https://doi.org/10.3390/ma14195515 - 23 Sep 2021

Cited by 9 | Viewed by 2490

Abstract

Due to the flammability of materials and the vastness of space, flashover fires of large-space timber structures pose a huge threat to lives as well as the structures themselves. Therefore, it is necessary to study the critical conditions, control factors and prediction methods [...] Read more.

Due to the flammability of materials and the vastness of space, flashover fires of large-space timber structures pose a huge threat to lives as well as the structures themselves. Therefore, it is necessary to study the critical conditions, control factors and prediction methods of flashover fires. To address this issue, hundreds of design conditions were simulated by Fire Dynamics Simulator (FDS) with variations in space size, the heat release rate (HRR) of fire source and fire growth type. A temperature–time model of the maximum temperature of the smoke layer near the ceiling (T_max) was established, and the critical condition that uses this model to predict the occurrence of flashover was determined. Furthermore, a mathematical formula was established that can accurately predict the flashover induction time when the T_max exceeds 400 °C. This research can provide a reference for the performance-based fire safety design of large-space timber structures. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 28768 KiB

Open AccessArticle

Effects of W Alloying on the Lattice Distortion and Wear Behavior of Laser Cladding AlCoCrFeNiW_x High-Entropy Alloy Coatings

by Tao Wu, Yunxiang Chen, Shuqin Shi, Mengting Wu, Wanyuan Gui, Yuanyuan Tan, Jiheng Li and Yuan Wu

Materials 2021, 14(18), 5450; https://doi.org/10.3390/ma14185450 - 21 Sep 2021

Cited by 11 | Viewed by 2622

Abstract

Friction and wear properties of hot working die steel at above 800 °C are of particular interest for high temperature applications. Here, novel AlCoCrFeNiW_x high-entropy alloy (HEA) coatings have been fabricated on the surface of hot working die steel by laser cladding. [...] Read more.

Friction and wear properties of hot working die steel at above 800 °C are of particular interest for high temperature applications. Here, novel AlCoCrFeNiW_x high-entropy alloy (HEA) coatings have been fabricated on the surface of hot working die steel by laser cladding. The effects of the as-prepared AlCoCrFeNiW_x HEA coatings on the microstructure and high temperature friction and wear behavior of hot working die steel are investigated through scanning electron microscopy (SEM), electron probe microanalysis (EPMA), X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS). Having benefited from the formation of W-rich intermetallic compounds after the addition of W elements, the high temperature wear resistance of the coatings is obviously improved, and friction coefficient shows a large fluctuation. The microstructural characteristics of the AlCoCrFeNiW_x HEA coatings after the high temperature wear resistance test shows a highly favorable impact on microstructure stability and wear resistance, due to its the strong lattice distortion effect of W element on BCC solid solutions and the second phase strengthening of the W-rich intermetallic compounds. These findings may provide a method to design the high temperature wear resistant coatings. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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20 pages, 5205 KiB

Open AccessReview

Current Status of Research on the Modification of Thermal Properties of Epoxy Resin-Based Syntactic Foam Insulation Materials

by Zhongyuan Zhang, Xiaohan Dai, Le Li, Songsong Zhou, Wei Xue, Yunpeng Liu and Hechen Liu

Polymers 2021, 13(18), 3185; https://doi.org/10.3390/polym13183185 - 19 Sep 2021

Cited by 9 | Viewed by 4187

Abstract

As a lightweight and highly insulating composite material, epoxy resin syntactic foam is increasingly widely used for insulation filling in electrical equipment. To avoid core burning and cracking, which are prone to occur during the casting process, the epoxy resin-based syntactic foam insulation [...] Read more.

As a lightweight and highly insulating composite material, epoxy resin syntactic foam is increasingly widely used for insulation filling in electrical equipment. To avoid core burning and cracking, which are prone to occur during the casting process, the epoxy resin-based syntactic foam insulation materials with high thermal conductivity and low coefficient of thermal expansion are required for composite insulation equipment. The review is divided into three sections concentrating on the two main aspects of modifying the thermal properties of syntactic foam. The mechanism and models, from the aspects of thermal conductivity and coefficient of thermal expansion, are presented in the first part. The second part aims to better understand the methods for modifying the thermal properties of syntactic foam by adding functional fillers, including the addition of thermally conductive particles, hollow glass microspheres, negative thermal expansion filler and fibers, etc. The third part concludes by describing the existing challenges in this research field and expanding the applicable areas of epoxy resin-based syntactic foam insulation materials, especially cross-arm composite insulation. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 4917 KiB

Open AccessArticle

Bond Properties of Carbon Fiber Reinforced Polymer and Corrosion-Cracked Reinforced Concrete Interface: Experimental Test and Nonlinear Degenerate Interface Law

by Yongzhi Gong, Yingjie Shan, Yuyuan Wu, Liping Wang, Xiaojie Liu and Faxing Ding

Materials 2021, 14(18), 5333; https://doi.org/10.3390/ma14185333 - 15 Sep 2021

Cited by 4 | Viewed by 2503

Abstract

Existing experimental research on bond properties of the interface between Carbon Fiber Reinforced Polymer (CFRP) and damaged concrete is limited, although CFRP strengthening technology has been widely used for corroded reinforced concrete structures. This work investigated the bond behavior of CFRP to the [...] Read more.

Existing experimental research on bond properties of the interface between Carbon Fiber Reinforced Polymer (CFRP) and damaged concrete is limited, although CFRP strengthening technology has been widely used for corroded reinforced concrete structures. This work investigated the bond behavior of CFRP to the corrosion-cracked concrete interface, in which three factors were considered for experimentation, including corrosion degree, concrete strength and concrete cover thickness. The tests were conducted by developing a self-balancing double shear lap test device. In addition, a corrosion scene was provided simultaneously to simulate the external corrosion environment. The results showed that three peeling modes of CFRP sheets were observed with respect to corrosion degrees of the steel bars. The effects of the three factors on the stripping bearing capacity and effective bond length of CFRP sheets were discussed by systematic parametric analysis. Finally, a nonlinear degenerate law of CFRP-to-concrete interface considering the corrosion degree was improved and verified in this study. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 4079 KiB

Open AccessArticle

High Response of Ethanol Gas Sensor Based on NiO-Doped Apple Pectin by the Solution Process

by Jia-Cheng Jian, Yu-Chi Chang, Sheng-Po Chang and Shoou-Jinn Chang

Coatings 2021, 11(9), 1073; https://doi.org/10.3390/coatings11091073 - 5 Sep 2021

Cited by 1 | Viewed by 2538

Abstract

Novel gas sensor devices, based on biomaterial apple pectin film (APN) doped with NiO, were fabricated for the first time using a solution processing technique. The device was then annealed in a microwave chamber. The structural, elemental, and surface morphology of the device [...] Read more.

Novel gas sensor devices, based on biomaterial apple pectin film (APN) doped with NiO, were fabricated for the first time using a solution processing technique. The device was then annealed in a microwave chamber. The structural, elemental, and surface morphology of the device was investigated, using TEM, XPS, and AFM, respectively. The as-fabricated film sensor possessed a superior sensing performance regarding ethanol gas, compared to the pure apple pectin film sensor. The response of the device was recorded at a maximum efficiency of 161. For a 10 ppm concentration of ethanol gas at an operational temperature of 250 °C, the response time was 1.379 s. Nevertheless, the sensing mechanism for the sensor device is also described thoroughly. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 6074 KiB

Open AccessArticle

Effects of Cu Addition on Mechanical Behaviour, Microstructural Evolution and Anti-Corrosion Performance of TiAl-Based Intermetallic Alloy under Different Strain Rates

by Cheng-Hsien Kuo, Tao-Hsing Chen and Ting-Yang Zeng

Materials 2021, 14(17), 5056; https://doi.org/10.3390/ma14175056 - 3 Sep 2021

Cited by 1 | Viewed by 1735

Abstract

TiAl-based intermetallic alloys are prepared with Cu concentrations of 3–5 at.% (atomic ratio). The mechanical properties and microstructural characteristics of the alloys are investigated under static and dynamic loading conditions using a material testing system (MTS) and split-Hopkinson Pressure Bar (SHPB), respectively. The [...] Read more.

TiAl-based intermetallic alloys are prepared with Cu concentrations of 3–5 at.% (atomic ratio). The mechanical properties and microstructural characteristics of the alloys are investigated under static and dynamic loading conditions using a material testing system (MTS) and split-Hopkinson Pressure Bar (SHPB), respectively. The electrochemical properties of the various alloys are then tested in Ringer’s solution. It is shown that the level of Cu addition significantly affects both the flow stress and the ductility of the samples. For Cu contents of 3 and 4 at.%, respectively, the flow stress and strain rate sensitivity increase at higher strain rates. Furthermore, for a constant strain rate, a Cu content of 4 at.% leads to an increased fracture strain. However, for the sample with the highest Cu addition of 5 at.%, the flow stress and fracture strain both decrease. The X-ray diffraction (XRD) patterns and optical microscopy (OM) images reveal that the lower ductility is due to the formation of a greater quantity of γ phase in the binary TiAl alloy system. Among all the specimens, that with a Cu addition of 4 at.% has the best anti-corrosion performance. Overall, the results indicate that the favourable properties of the TiAlCu₄ sample stem mainly from the low γ phase content of the microstructure and the high α₂ phase content. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 2412 KiB

Open AccessArticle

An Ultrawideband Polarization-Insensitive Diffusion Metasurface Using Period Changed Unit Cell for RCS Reduction

by Jianzhong Chen, Chengwei Zhang, Yutong Zhao, Lei Lin, Liang Li, Tao Su, Bian Wu and Jinshan Ding

Materials 2021, 14(17), 5053; https://doi.org/10.3390/ma14175053 - 3 Sep 2021

Cited by 4 | Viewed by 2265

Abstract

A polarization-insensitive diffusion metasurface using a period-changed unit cell is presented for reducing the radar cross-section (RCS) of metallic objects in ultrawideband. Two metallic Minkowski loops are proposed as coding elements, different from traditional designs. The “0” element is constructed by period-changed unit [...] Read more.

A polarization-insensitive diffusion metasurface using a period-changed unit cell is presented for reducing the radar cross-section (RCS) of metallic objects in ultrawideband. Two metallic Minkowski loops are proposed as coding elements, different from traditional designs. The “0” element is constructed by period-changed unit cells to achieve a 180 ± 30° phase difference with the same reflection amplitude of nearly −0.9 dB in an ultrawideband from 7.1 to 29.2 GHz. Multilayer geometry with a thickness of 4.5 mm (about 0.105λ₀ at the lowest operating frequency) and rotational symmetry loops are used to realize the ultrawideband characteristic and polarization-insensitive behavior. For verification, a polarization-insensitive diffusion metasurface is designed, fabricated, and measured. The simulated and measured results of the diffusion metasurface are in good consistency and the results both show that the metasurface enables a 10 dB backscattering reduction over an amazing ultrawideband ranging from 7.1 to 29.2 GHz (BW of 122%). Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 3537 KiB

Open AccessArticle

Preparation and Application of Fluorine-Free Finishing Agent with Excellent Water Repellency for Cotton Fabric

by Chengbing Yu, Kaiqin Shi, Jinyan Ning, Zhe Zheng, Hualong Yu, Zhenxuan Yang and Jun Liu

Polymers 2021, 13(17), 2980; https://doi.org/10.3390/polym13172980 - 2 Sep 2021

Cited by 7 | Viewed by 4130

Abstract

Water repellent is an important functional finish for cotton fabric. However, cotton fabrics often have poor washing resistance and other performances after actual finishing. In this study, based on the structural characteristics of cotton fiber and durability of water repellent, a cross-linked amino [...] Read more.

Water repellent is an important functional finish for cotton fabric. However, cotton fabrics often have poor washing resistance and other performances after actual finishing. In this study, based on the structural characteristics of cotton fiber and durability of water repellent, a cross-linked amino long-chain alkyl polysiloxane (CAHPS) was first prepared, and then reacted with modified silica. Finally, a chemically bonded organic–inorganic nanohybrid cross-linked polysiloxane (rSiO₂–CAHPS) was fabricated. Furthermore, the rSiO₂–CAHPS was emulsified to obtain a durable fluorine-free water repellent. The water repellent finishing for cotton fabric was carried out by the pad–dry–cure process. After finishing, the cotton fabric had good resistance to conventional liquids and excellent washing resistance, and still maintained good water repellency after 30 rounds of soaping. Moreover, properties including air permeability, mechanical property and whiteness are hardly affected after finishing. SEM and XPS characterization show that a layer of dense silicon film is formed on the surface of cotton fabric by rSiO₂–CAHPS water repellent. The existence of nanosilica can improve the surface roughness of cotton fibers. The synergistic effect of fiber matrix, nanoparticles and CAHPS endows the fabric with a micro/nano-multi-scale micro-rough structure, which improves the water repellency of cotton fabric after water repellent finishing. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 4224 KiB

Open AccessFeature PaperArticle

Sustainably Processed Waste Wool Fiber-Reinforced Biocomposites for Agriculture and Packaging Applications

by Parag Bhavsar, Tudor Balan, Giulia Dalla Fontana, Marina Zoccola, Alessia Patrucco and Claudio Tonin

Fibers 2021, 9(9), 55; https://doi.org/10.3390/fib9090055 - 1 Sep 2021

Cited by 11 | Viewed by 3770

Abstract

In the EU, sheep bred for dairy and meat purposes are of low quality, their economic value is not even enough to cover shearing costs, and their wool is generally seen as a useless by-product of sheep farming, resulting in large illegal disposal [...] Read more.

In the EU, sheep bred for dairy and meat purposes are of low quality, their economic value is not even enough to cover shearing costs, and their wool is generally seen as a useless by-product of sheep farming, resulting in large illegal disposal or landfilling. In order to minimize environmental and health-related problems considering elemental compositions of discarded materials such as waste wool, there is a need to recycle and reuse waste materials to develop sustainable innovative technologies and transformation processes to achieve sustainable manufacturing. This study aims to examine the application of waste wool in biocomposite production with the help of a sustainable hydrolysis process without any chemicals and binding material. The impact of superheated water hydrolysis and mixing hydrolyzed wool fibers with kraft pulp on the performance of biocomposite was investigated and characterized using SEM, FTIR, tensile strength, DSC, TGA, and soil burial testing in comparison with 100% kraft pulp biocomposite. The superheated water hydrolysis process increases the hydrophilicity and homogeneity and contributes to increasing the speed of biodegradation. The biocomposite is entirely self-supporting, provides primary nutrients for soil nourishment, and is observed to be completely biodegradable when buried in the soil within 90 days. Among temperatures tested for superheated water hydrolysis of raw wool, 150 °C seems to be the most appropriate for the biocomposite preparation regarding physicochemical properties of wool and suitability for wool mixing with cellulose. The combination of a sustainable hydrolysis process and the use of waste wool in manufacturing an eco-friendly, biodegradable paper/biocomposite will open new potential opportunities for the utilization of waste wool in agricultural and packaging applications and minimize environmental impact. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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15 pages, 3898 KiB

Open AccessArticle

Improvement in Solubility and Absorption of Nifedipine Using Solid Solution: Correlations between Surface Free Energy and Drug Dissolution

by Sukannika Tubtimsri and Yotsanan Weerapol

Polymers 2021, 13(17), 2963; https://doi.org/10.3390/polym13172963 - 31 Aug 2021

Cited by 6 | Viewed by 2898

Abstract

Ternary solid solutions composed of nifedipine (NDP), amino methacrylate copolymer (AMCP), and polysorbate (PS) 20, 60, or 65 were prepared using a solvent evaporation method. The dissolution profiles of NDP were used to study the effect of the addition of polysorbate based on [...] Read more.

Ternary solid solutions composed of nifedipine (NDP), amino methacrylate copolymer (AMCP), and polysorbate (PS) 20, 60, or 65 were prepared using a solvent evaporation method. The dissolution profiles of NDP were used to study the effect of the addition of polysorbate based on hydrophilic properties. A solid solution of NDP and AMCP was recently developed; however, the dissolution of NDP was <70%. In the present study, polysorbate was added to improve the dissolution of the drug by altering its hydrophilicity. The suitable formulation contained NDP and AMCP at a ratio of 1:4 and polysorbate at a concentration of 0.1%, 0.3%, or 0.6%. Differential scanning calorimetry and powder X-ray diffraction were used to examine the solid solutions. No peak representing crystalline NDP was observed in any solid solution samples, suggesting that the drug was molecularly dispersed in AMCP. The NDP dissolution from NDP powder and solid solution without PS were 16.82% and 58.19%, respectively. The highest dissolution of NDP of approximately 95.25% was noted at 120 min for the formulation containing 0.6% PS20. Linear correlations were observed between the surface free energy and percentages of dissolved NDP (R² = 0.7115–0.9315). Cellular uptake across Caco-2 was selected to determine the drug permeability. The percentages of cellular uptake from the NDP powder, solid solution without and with PS20 were 0.25%, 3.60%, and 7.27%, respectively. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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9 pages, 4281 KiB

Open AccessArticle

Valley Vortex Assisted and Topological Protected Microparticles Manipulation with Complicated 2D Patterns in a Star-like Sonic Crystal

by Jian Zhu, Tianning Chen, Chen Chen and Wei Ding

Materials 2021, 14(17), 4939; https://doi.org/10.3390/ma14174939 - 30 Aug 2021

Cited by 3 | Viewed by 2355

Abstract

Arranging microparticles into desired patterns, especially in a complicated pattern with a reliable and tunable manner, is challenging but highly desirable in the fields such as biomedicine and tissue engineering. To overcome these limitations, here, by using the concept of topology in acoustics, [...] Read more.

Arranging microparticles into desired patterns, especially in a complicated pattern with a reliable and tunable manner, is challenging but highly desirable in the fields such as biomedicine and tissue engineering. To overcome these limitations, here, by using the concept of topology in acoustics, the valley vortex is utilized to manipulate particles on a large scale with complicated 2D patterns in the star-like sonic crystals at different frequencies. A topologically protected edge state is obtained at the interface of the crystals with different valley Hall phases, which shows the ability of reliable microparticles control along the sharp corner and the capability of robust particles cluster aggregation in a defective system. The results may provide intriguing resources for future microfluidic systems in a complicated and brittle environment. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 24293 KiB

Open AccessArticle

Comparison of Three Interfacial Conductive Networks Formed in Carbon Black-Filled PA6/PBT Blends

by Hansong Li, Xinlin Tuo, Bao-Hua Guo, Jian Yu and Zhao-Xia Guo

Polymers 2021, 13(17), 2926; https://doi.org/10.3390/polym13172926 - 30 Aug 2021

Cited by 6 | Viewed by 2695

Abstract

Interfacial localization of carbon fillers in cocontinuous-structured polymer blends is well-known as a high-efficiency strategy for conductive network formation. However, a comparison with interfacial localization of carbon fillers in sea-island-structured polymer blends is lacking. Here, three types of highly efficient conductive networks formed [...] Read more.

Interfacial localization of carbon fillers in cocontinuous-structured polymer blends is well-known as a high-efficiency strategy for conductive network formation. However, a comparison with interfacial localization of carbon fillers in sea-island-structured polymer blends is lacking. Here, three types of highly efficient conductive networks formed on the basis of interfacial localization of carbon black (CB) in polyamide 6 (PA6)/poly(butylene terephthalate) (PBT) blends with different blend compositions (80/20, 50/50 and 20/80 vol/vol) were investigated and compared in terms of electrical resistivity, morphology as well as rheological and mechanical properties. The order of the electrical percolation threshold of CB in the three blends is 50/50 < 20/80 < 80/20, which can be attributed to different network structures. The rheological percolation thresholds are close to the electrical ones, confirming the formation of CB networks. The formation mechanisms for the three types of CB network structures are analyzed. All the three types of PA6/PBT-6 vol% CB composites showed improved tensile strength compared with PA6/PBT blends, being in favor for practical applications. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 3219 KiB

Open AccessArticle

The Influence of Li⁺ and K⁺ Added Cations and Annealing Temperature on the Magnetic and Dielectric Properties of Mg-Zn Ferrite

by Iulian Petrila and Florin Tudorache

Materials 2021, 14(17), 4916; https://doi.org/10.3390/ma14174916 - 29 Aug 2021

Cited by 3 | Viewed by 2104

Abstract

This paper presents the results of an investigation on the magnetic and dielectric properties of Mg_0.5Zn_0.5Fe₂O₄ spinel ferrite with a 1% weight percentage of Li⁺ and K⁺ added cations. The addition of metal ions [...] Read more.

This paper presents the results of an investigation on the magnetic and dielectric properties of Mg_0.5Zn_0.5Fe₂O₄ spinel ferrite with a 1% weight percentage of Li⁺ and K⁺ added cations. The addition of metal ions plays an important role in increasing the porosity and favors the formation of ferrite at low temperatures. The goal of this new research is to demonstrate that by selecting the type of metallic cations for addition or choosing an optimal sintering temperature, it may be possible to improve the magnetic and electrical properties of Mg-Zn ferrite. The samples were prepared using sol-gel self-combustion techniques and annealed at 1000 °C, 1100 °C, and 1200 °C. Scanning electron microscopy revealed the shape and grain size of the samples, and the phase composition was analyzed using the X-ray diffraction technique. The magnetic information, such as remanent magnetization M_R, saturation magnetization M_S, and coercivity H_C, were extracted from the hysteresis loops of the samples. The electrical investigation was focused on the low- and high-frequency dependence of dielectric constant and dielectric losses. The results are discussed in terms of microstructural changes induced by the additions of Li⁺ and K⁺ metallic cations. Conclusions are drawn concerning the optimization of magnetic and electrical properties for the development of Mg-Zn ferrite with possible applications in the field of magnetic materials or electronics. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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9 pages, 4886 KiB

Open AccessArticle

High Performance Valve Seat Materials for CNG Powered Combustion Engines

by Andrzej Romański and Elżbieta Cygan-Bączek

Materials 2021, 14(17), 4860; https://doi.org/10.3390/ma14174860 - 26 Aug 2021

Cited by 2 | Viewed by 2754

Abstract

The conventional copper infiltrated high speed steel (HSS) valve seats used in gasoline engines are not suitable for CNG combustion because the exhaust gas temperature is at least 80 °C higher, which drastically shortens the service life of the engine valves. Therefore, a [...] Read more.

The conventional copper infiltrated high speed steel (HSS) valve seats used in gasoline engines are not suitable for CNG combustion because the exhaust gas temperature is at least 80 °C higher, which drastically shortens the service life of the engine valves. Therefore, a proprietary high-alloy HSS-base material was designed to combat hot corrosion and mechanical wear of valve seat faces in CNG fuelled engines. A batch of −100 mesh water atomized HSS powder was commissioned. The powder was vacuum annealed in order to reduce oxygen content and increase its compressibility. To improve the final part machinability, 1.2% MnS was admixed to the HSS powder prior to compaction. The green compacts were sintered at 1135 °C in nitrogen to around 83% TD and subsequently infiltrated with a copper alloy. After installing the valve seat components on a cylinder head, the engine was tested for 100 h according to the automotive industry valve seat wear test procedures. Both the periodic 8-h checks as well as the final examination of the valve seats showed very slow wear, indicating their suitability for CNG powered engines. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 4382 KiB

Open AccessArticle

Modified Grape Seeds: A Promising Alternative for Nitrate Removal from Water

by Marija Stjepanović, Natalija Velić and Mirna Habuda-Stanić

Materials 2021, 14(17), 4791; https://doi.org/10.3390/ma14174791 - 24 Aug 2021

Cited by 5 | Viewed by 2442

Abstract

The aim of this work was to investigate grape seeds as a potential adsorbent for nitrate removal from water. Grape seeds were modified by quaternization and the applicability of the modified grape seeds (MGS) was evaluated in batch adsorption experiments. Fixed bed adsorption [...] Read more.

The aim of this work was to investigate grape seeds as a potential adsorbent for nitrate removal from water. Grape seeds were modified by quaternization and the applicability of the modified grape seeds (MGS) was evaluated in batch adsorption experiments. Fixed bed adsorption and regeneration studies were carried out to determine the regeneration capacity of MGS. The maximum adsorption capacity of 25.626 mg g⁻¹ at native pH (6.3) for nitrate removal by MSG was comparable to that of the commercial anion exchange resin Relite A490 under similar conditions. The percent removal of nitrate from model nitrate solution was 86.47% and 93.25% for MGS, and Relite A490, respectively, and in synthetic wastewater 57.54% and 78.37%. Analysis of the batch adsorption data using isotherm models revealed that the Freundlich model provided a better fit to the data obtained than the Langmuir model, indicating multilayer adsorption. In kinetic terms, the results showed that the adsorption followed the pseudo-first order model. By investigating the adsorption mechanism, the results suggest that the intraparticle diffusion model was not the only process controlling the adsorption of nitrate on MGS. In column experiments (adsorption/desorption studies), three adsorption cycles were tested with minimal decrease in adsorption capacities, implying that this alternative adsorbent can be successfully regenerated and reused. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 1620 KiB

Open AccessArticle

Radio-Oxidation Ageing of XLPE Containing Different Additives and Filler: Effect on the Gases Emission and Consumption

by Muriel Ferry, Floriane Carpentier and Manon Cornaton

Polymers 2021, 13(17), 2845; https://doi.org/10.3390/polym13172845 - 24 Aug 2021

Cited by 4 | Viewed by 2139

Abstract

In the lifetime extension of nuclear power plants (NPPs) context, aging of electric cables has to be very well understood in order to predict their end-of-life and thus to replace them on time. Therefore, evaluation and understanding of the ageing mechanism of the [...] Read more.

In the lifetime extension of nuclear power plants (NPPs) context, aging of electric cables has to be very well understood in order to predict their end-of-life and thus to replace them on time. Therefore, evaluation and understanding of the ageing mechanism of the cable insulating material is mandatory under conditions as close as possible of those encountered in NPPs. In this context, different formulated crosslinked polyethylenes (XLPE)—one of the polymers used nowadays to manufacture the insulator layer—have been irradiated under oxidative conditions, at two different dose rates and at different aging doses. Gases emitted and consumed from the irradiated polymers were quantified to identify the primary processes happening in the materials and thus the interactions involved between the different molecules composing the formulated polymers. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 3333 KiB

Open AccessArticle

A Method for Preparing Superhydrophobic Paper with High Stability and Ionic Liquid-Induced Wettability Transition

by Shangjie Jiang, Shisheng Zhou and Bin Du

Materials 2021, 14(16), 4638; https://doi.org/10.3390/ma14164638 - 18 Aug 2021

Cited by 3 | Viewed by 1984

Abstract

In this study, the polymer PTSPM-PMETAC with anion adsorption properties was prepared by a one-step method, then the amino-modified nano-SiO₂ was grafted onto the polymer to improve the roughness of the surface and enhance the stability of superhydrophobic properties, and a high-stability [...] Read more.

In this study, the polymer PTSPM-PMETAC with anion adsorption properties was prepared by a one-step method, then the amino-modified nano-SiO₂ was grafted onto the polymer to improve the roughness of the surface and enhance the stability of superhydrophobic properties, and a high-stability superhydrophobic paper with ion-induced wettability transition properties was successfully prepared. The study found that the paper can realize the reversible control of surface wettability through the exchange between the anions PF₆⁻ and Cl⁻ adsorbed on the surface of PMETAC, and further investigation of the effect of different solvents on the ion exchange properties found that water was the poor solvent for ion exchange, while the mixtures of methanol, acetone, and methanol & water were the good solvent. On the whole, the preparation of superhydrophobic paper by this method not only simple in preparation process, low in cost and strong in universality, but also the prepared superhydrophobic paper has high transparency and good stability, which has great application potential in industrial production. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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18 pages, 6695 KiB

Open AccessArticle

Anti-Corrosion Behavior of Olmesartan for Soft-Cast Steel in 1 mol dm⁻³ HCl

by B. M. Praveen, A. Alhadhrami, B. M. Prasanna, Narayana Hebbar and Radhakrishna Prabhu

Coatings 2021, 11(8), 965; https://doi.org/10.3390/coatings11080965 - 13 Aug 2021

Cited by 10 | Viewed by 2194

Abstract

This study discusses the effects of temperature on corrosion inhibition for soft-cast steel by the pharmaceutically active drug olmesartan in 1 mol dm⁻³ HCl. The sufficient number of electron-rich elements and non-bonding π electrons in its structure favored a good capability for [...] Read more.

This study discusses the effects of temperature on corrosion inhibition for soft-cast steel by the pharmaceutically active drug olmesartan in 1 mol dm⁻³ HCl. The sufficient number of electron-rich elements and non-bonding π electrons in its structure favored a good capability for coating onto the electron-deficient steel surfaces. Theoretical and electrochemical measurements were carried out at the temperature region of 303 K to 333 K. Therefore, the experiment suggests that the inhibition efficiency of olmesartan increases with its increasing concentrations due to the adsorption. Additionally, even at a higher temperature of 333 K, the inhibitor molecules attain their stability towards corrosion resistance of steel surfaces. The adsorption of inhibitors on steel surfaces is spontaneously found to include the mixture of physisorption and chemisorption, and it obeys Temkin’s adsorption isotherm model. Theoretical and computational considerations were made using quantum chemical parameters and molecular dynamics simulations, which confirmed that the olmesartan has a suitable corrosion inhibitive capability intended for soft-cast steel in 1 mol dm⁻³ HCl. Additionally, scanning electron microscopic measurement was used to obtain a visual idea of the inhibitive action of the inhibitor attained by forming an adsorbed protective layer onto the steel surfaces. The minute concentration of olmesartan of about 10–50 ppm shows high inhibition efficiency of ~80%, even at elevated temperatures. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 2287 KiB

Open AccessArticle

Enhanced Electron Heat Conduction in TaS₃ 1D Metal Wire

by Hojoon Yi, Jaeuk Bahng, Sehwan Park, Dang Xuan Dang, Wonkil Sakong, Seungsu Kang, Byung-wook Ahn, Jungwon Kim, Ki Kang Kim, Jong Tae Lim and Seong Chu Lim

Materials 2021, 14(16), 4477; https://doi.org/10.3390/ma14164477 - 10 Aug 2021

Cited by 2 | Viewed by 2889

Abstract

The 1D wire TaS₃ exhibits metallic behavior at room temperature but changes into a semiconductor below the Peierls transition temperature (T_p), near 210 K. Using the 3ω method, we measured the thermal conductivity

κ

of TaS₃ as a [...] Read more.

The 1D wire TaS₃ exhibits metallic behavior at room temperature but changes into a semiconductor below the Peierls transition temperature (T_p), near 210 K. Using the 3ω method, we measured the thermal conductivity

κ

of TaS₃ as a function of temperature. Electrons dominate the heat conduction of a metal. The Wiedemann–Franz law states that the thermal conductivity

κ

of a metal is proportional to the electrical conductivity σ with a proportional coefficient of L₀, known as the Lorenz number—that is,

κ = σ L_{o} T

. Our characterization of the thermal conductivity of metallic TaS₃ reveals that, at a given temperature T, the thermal conductivity κ is much higher than the value estimated in the Wiedemann–Franz (W-F) law. The thermal conductivity of metallic TaS₃ was approximately 12 times larger than predicted by W-F law, implying

L = 12 L_{0}

. This result implies the possibility of an existing heat conduction path that the Sommerfeld theory cannot account for. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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16 pages, 5606 KiB

Open AccessArticle

An Insight into Nano Silver Fluoride-Coated Silk Fibroin Bioinspired Membrane Properties for Guided Tissue Regeneration

by Aditi Pandey, Tzu-Sen Yang, Ta-I Yang, Wendimi Fatimata Belem, Nai-Chia Teng, I-Wen Chen, Ching-Shuan Huang, Aivaras Kareiva and Jen-Chang Yang

Polymers 2021, 13(16), 2659; https://doi.org/10.3390/polym13162659 - 10 Aug 2021

Cited by 8 | Viewed by 3237

Abstract

The current work focuses on the development of a novel electrospun silk fibroin (SF) nonwoven mat as a GTR membrane with antibacterial, biomineralization and biocompatible properties. The γ-poly glutamic acid (γ-PGA)-capped nano silver fluoride (NSF) and silver diamine fluoride (SDF) were first synthesized, [...] Read more.

The current work focuses on the development of a novel electrospun silk fibroin (SF) nonwoven mat as a GTR membrane with antibacterial, biomineralization and biocompatible properties. The γ-poly glutamic acid (γ-PGA)-capped nano silver fluoride (NSF) and silver diamine fluoride (SDF) were first synthesized, which were dip-coated onto electrospun silk fibroin mats (NSF-SF and SDF-SF). UV-Vis spectroscopy and TEM depicted the formation of silver nanoparticles. NSF-SF and SDF-SF demonstrated antibacterial properties (against Porphyromonas gingivalis) with 3.1 and 6.7 folds higher relative to SF, respectively. Post-mineralization in simulated body fluid, the NSF-SF effectively promoted apatite precipitation (Ca/P ~1.67), while the SDF-SF depicted deposition of silver nanoparticles, assessed by SEM-EDS. According to the FTIR-ATR deconvolution analysis, NSF-SF portrayed ~75% estimated hydroxyapatite crystallinity index (CI), whereas pure SF and SDF-SF demonstrated ~60%. The biocompatibility of NSF-SF was ~82% when compared to the control, while SDF-coated samples revealed in vitro cytotoxicity, further needing in vivo studies for a definite conclusion. Furthermore, the NSF-SF revealed the highest tensile strength of 0.32 N/mm and 1.76% elongation at break. Therefore, it is substantiated that the novel bioactive and antibacterial NSF-SF membranes can serve as a potential candidate, shedding light on further in-depth analysis for GTR applications. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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11 pages, 959 KiB

Open AccessArticle

Study of the Relationship between the Structural Parameters of Magnetic Polypropylene-Knitted Fabric and Human Skin Microcirculation

by Zimin Jin, Si Chen, Jing Jin, Kunying Chen, Yuqiang Sun and Mingtao Zhao

Materials 2021, 14(16), 4368; https://doi.org/10.3390/ma14164368 - 4 Aug 2021

Cited by 3 | Viewed by 2258

Abstract

In this paper, the effects of the structural parameters of magnetic-knitted fabric on human skin microcirculation (HSM) were studied in relation to magnetic polypropylene yarn, which was used as raw material. Three experimental factors were designed: the magnetic powder content of polypropylene, the [...] Read more.

In this paper, the effects of the structural parameters of magnetic-knitted fabric on human skin microcirculation (HSM) were studied in relation to magnetic polypropylene yarn, which was used as raw material. Three experimental factors were designed: the magnetic powder content of polypropylene, the feeding ratio of magnetic polypropylene (MP) and graphene viscous (GV), and stitch. Twelve pieces of seamless knitted fabric were prepared according to the comprehensive experimental design method. The BIV angiography was used to proceed with an HSM test of about 12 pieces of seamless knitted fabric. The results show the following: The magnetic powder content of polypropylene has the greatest influence on the blood flow promotion multiples of skin–blood microcirculation, followed by the feeding ratio of MP and GV, while stitch has the least influence. When the plating yarn feeding ratio was 100:0, the magnetic powder content of polypropylene was 50%, and the stitch was 1 + 1 false rib, meaning that the fabric could promote HSM more efficiently. This is compared against the common polypropylene knitted fabric, where the blood flow promotion multiples increased by 9.87%. The purpose of this study was to explore the structural parameters of magnetic polypropylene-knitted fabric that has a better effect on promoting HSM, and to provide a reference for the development of functional health-knitted fabrics. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 2868 KiB

Open AccessArticle

Antibacterial and Freshness-Preserving Mechanisms of Chitosan-Nano-TiO₂-Nano-Ag Composite Materials

by Zihao Dong, Ran Li and Yan Gong

Coatings 2021, 11(8), 914; https://doi.org/10.3390/coatings11080914 - 30 Jul 2021

Cited by 8 | Viewed by 3437

Abstract

With chitosan, nano-TiO₂ and nano-Ag as raw materials, nano-TiO₂ and nano-TiO₂-Ag were modified by a surface modifier-sodium laurate. Chitosan (CTS), chitosan-nano-TiO₂ (CTS-TiO₂), and chitosan-nano-TiO₂-nano-Ag (CTS-TiO₂-Ag) composite materials and corresponding films were prepared [...] Read more.

With chitosan, nano-TiO₂ and nano-Ag as raw materials, nano-TiO₂ and nano-TiO₂-Ag were modified by a surface modifier-sodium laurate. Chitosan (CTS), chitosan-nano-TiO₂ (CTS-TiO₂), and chitosan-nano-TiO₂-nano-Ag (CTS-TiO₂-Ag) composite materials and corresponding films were prepared by a solution co-blending method. Then, the antibacterial performances of the above three types of materials against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis were compared. Moreover, potato and strawberry weight loss rates, peroxidase activity, and vitamin C contents after different film coating treatments were measured. Compared with CTS films, the CTS-TiO₂-Ag and CTS-TiO₂ composite films both showed better physical properties, and both demonstrated higher antibacterial effects, especially for E. coli. Measurement of physiological indices in fruits and vegetables showed that the freshness-preserving effect of CTS-TiO₂-Ag coating films was the most significant. In all, the CTS-TiO₂-Ag coating films can actively contribute to the storage of fruits and vegetables at room temperature, and better ensure product quality. Thus, such films are meaningful for research and development of new fruit freshness-keeping techniques and materials. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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12 pages, 3298 KiB

Open AccessArticle

Acoustic Metasurface-Aided Broadband Noise Reduction in Automobile Induced by Tire-Pavement Interaction

by Hyeonu Heo, Mathew Sofield, Jaehyung Ju and Arup Neogi

Materials 2021, 14(15), 4262; https://doi.org/10.3390/ma14154262 - 30 Jul 2021

Cited by 7 | Viewed by 2848

Abstract

The primary noise sources of the vehicle are the engine, exhaust, aeroacoustic noise, and tire–pavement interaction. Noise generated by the first three factors can be reduced by replacing the combustion engine with an electric motor and optimizing aerodynamic design. Currently, a dominant noise [...] Read more.

The primary noise sources of the vehicle are the engine, exhaust, aeroacoustic noise, and tire–pavement interaction. Noise generated by the first three factors can be reduced by replacing the combustion engine with an electric motor and optimizing aerodynamic design. Currently, a dominant noise within automobiles occurs from the tire–pavement interaction over a speed of 70–80 km/h. Most noise suppression efforts aim to use sound absorbers and cavity resonators to narrow the bandwidth of acoustic frequencies using foams. We demonstrate a technique utilizing acoustic metasurfaces (AMSes) with high reflective characteristics using relatively lightweight materials for noise reduction without any change in mechanical strength or weight of the tire. A simple technique is demonstrated that utilizes acoustic metalayers with high reflective characteristics using relatively lightweight materials for noise reduction without any change in mechanical strength or weight of the tire. The proposed design can significantly reduce the noise arising from tire–pavement interaction over a broadband of acoustic frequencies under 1000 Hz and over a wide range of vehicle speeds using a negative effective dynamic mass density approach. The experiment demonstrated that the sound transmission loss of AMSes is 2–5 dB larger than the acoustic foam near the cavity mode, at 200–300 Hz. The proposed approach can be extended to the generalized area of acoustic and vibration isolation. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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14 pages, 6218 KiB

Open AccessArticle

Influence of Manufacturing Process in Structural Health Monitoring and Mechanical Behaviour of CNT Reinforced CFRP and Ti6Al4V Multi-Material Joints

by S. Dasilva, A. Jimenez-Suarez, E. Rodríguez and S. G. Prolongo

Polymers 2021, 13(15), 2488; https://doi.org/10.3390/polym13152488 - 28 Jul 2021

Cited by 4 | Viewed by 2502

Abstract

Co-cured multi-material metal–polymer composites joints are recent interesting structural materials for locally reinforcing a structure in specific areas of high structural requirements, in fibre metal laminates and lightweight high-performance structures. The influence of manufacturing processes on the morphological quality and their mechanical behaviour [...] Read more.

Co-cured multi-material metal–polymer composites joints are recent interesting structural materials for locally reinforcing a structure in specific areas of high structural requirements, in fibre metal laminates and lightweight high-performance structures. The influence of manufacturing processes on the morphological quality and their mechanical behaviour has been analysed on joints constituted by sol-gel treated Ti6Al4V and carbon fibre reinforced composites (CFRP). In addition, carbon nanotubes (CNT) have been added to an epoxy matrix to develop multiscale CNT reinforced CFRP, increasing their electrical conductivity and allowing their structural health monitoring (SHM). Mechanical behaviour of manufactured multi-material joints is analysed by the measurement of lap shear strength (LSS) and Mode I adhesive fracture energy (GIC) using double cantilever beam specimens (DCB). It has been proven that the addition of MWCNT improves the conductivity of the multi-material joints, even including surface treatment with sol-gel, allowing structural health monitoring (SHM). Moreover, it has been proven that the manufacturing process affects the polymer interface thickness and the porosity, which strongly influence the mechanical and SHM behaviour. On the one hand, the increase in the adhesive layer thickness leads to a great improvement in mode I fracture energy. On the other hand, a lower interface thickness enhances the SHM sensibility due to the proximity between MWCNT and layers of conductive substrates, carbon woven and titanium alloy. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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17 pages, 5562 KiB

Open AccessArticle

Pectin/Activated Carbon-Based Porous Microsphere for Pb²⁺ Adsorption: Characterization and Adsorption Behaviour

by Ri-si Wang, Ya Li, Xi-xiang Shuai, Rui-hong Liang, Jun Chen and Cheng-mei Liu

Polymers 2021, 13(15), 2453; https://doi.org/10.3390/polym13152453 - 26 Jul 2021

Cited by 27 | Viewed by 3632

Abstract

The development of effective heavy metal adsorbents has always been the goal of environmentalists. Pectin/activated carbon microspheres (P/ACs) were prepared through simple gelation without chemical crosslinking and utilized for adsorption of Pb²⁺. Scanning electron microscopy (SEM) revealed that the addition of [...] Read more.

The development of effective heavy metal adsorbents has always been the goal of environmentalists. Pectin/activated carbon microspheres (P/ACs) were prepared through simple gelation without chemical crosslinking and utilized for adsorption of Pb²⁺. Scanning electron microscopy (SEM) revealed that the addition of activated carbon increased the porosity of the microsphere. Texture profile analysis showed good mechanical strength of P/ACs compared with original pectin microspheres. Kinetic studies found that the adsorption process followed a pseudo-second-order model, and the adsorption rate was controlled by film diffusion. Adsorption isotherms were described well by a Langmuir isotherm model, and the maximum adsorption capacity was estimated to be 279.33 mg/g. The P/ACs with the highest activated carbon (P/AC_2:3) maintained a removal rate over 95.5% after 10 adsorption/desorption cycles. SEM-energy-dispersive X-ray spectrum and XPS analysis suggested a potential mechanism of adsorption are ion exchange between Pb²⁺ and Ca²⁺, electronic adsorption, formation of complexes, and physical adsorption of P/ACs. All the above results indicated the P/ACs may be a good candidate for the adsorption of Pb²⁺. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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26 pages, 1834 KiB

Open AccessReview

Multipurpose Prevention Technologies: Oral, Parenteral, and Vaginal Dosage Forms for Prevention of HIV/STIs and Unplanned Pregnancy

by Isabella C. Young and Soumya Rahima Benhabbour

Polymers 2021, 13(15), 2450; https://doi.org/10.3390/polym13152450 - 26 Jul 2021

Cited by 13 | Viewed by 6272

Abstract

There is a high global prevalence of HIV, sexually transmitted infections (STIs), and unplanned pregnancies. Current preventative daily oral dosing regimens can be ineffective due to low patient adherence. Sustained release delivery systems in conjunction with multipurpose prevention technologies (MPTs) can reduce high [...] Read more.

There is a high global prevalence of HIV, sexually transmitted infections (STIs), and unplanned pregnancies. Current preventative daily oral dosing regimens can be ineffective due to low patient adherence. Sustained release delivery systems in conjunction with multipurpose prevention technologies (MPTs) can reduce high rates of HIV/STIs and unplanned pregnancies in an all-in-one efficacious, acceptable, and easily accessible technology to allow for prolonged release of antivirals and contraceptives. The concept and development of MPTs have greatly progressed over the past decade and demonstrate efficacious technologies that are user-accepted with potentially high adherence. This review gives a comprehensive overview of the latest oral, parenteral, and vaginally delivered MPTs in development as well as drug delivery formulations with the potential to advance as an MPT, and implementation studies regarding MPT user acceptability and adherence. Furthermore, there is a focus on MPT intravaginal rings emphasizing injection molding and hot-melt extrusion manufacturing limitations and emerging fabrication advancements. Lastly, formulation development considerations and limitations are discussed, such as nonhormonal contraceptive considerations, challenges with achieving a stable coformulation of multiple drugs, achieving sustained and controlled drug release, limiting drug–drug interactions, and advancing past preclinical development stages. Despite the challenges in the MPT landscape, these technologies demonstrate the potential to bridge gaps in preventative sexual and reproductive health care. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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20 pages, 2009 KiB

Open AccessArticle

Optimisation of AgNP Synthesis in the Production and Modification of Antibacterial Cellulose Fibres

by Emilia Smiechowicz, Barbara Niekraszewicz and Piotr Kulpinski

Materials 2021, 14(15), 4126; https://doi.org/10.3390/ma14154126 - 24 Jul 2021

Cited by 6 | Viewed by 2731

Abstract

The main aim of the presented research is to determine the optimal conditions for the production of silver nanoparticles (AgNPs) in N-methylmorpholine-N-oxide (NMMO), which will potentially allow to obtain small nanoparticles with uniform diameter distribution. In this paper, NMMO is used in the [...] Read more.

The main aim of the presented research is to determine the optimal conditions for the production of silver nanoparticles (AgNPs) in N-methylmorpholine-N-oxide (NMMO), which will potentially allow to obtain small nanoparticles with uniform diameter distribution. In this paper, NMMO is used in the fibre production process, both as a direct cellulose solvent and as an Ag+ reducing system. From an industrial point of view, this method is very promising because it allows to reduce the amount of used chemicals. The UV/Vis, DLS and TEM analysis proved that the synthesis temperature and time could play a key role in nanoparticle growth control in NMMO. It was found that the optimal conditions for AgNPs synthesis are 100 °C and 0.33 h. The estimations of the antibacterial activity of the fibres were completed. The applied AgNPs synthesis conditions allow to obtain antibacterial fibres with a wide range of applications, mainly in medicine. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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13 pages, 2509 KiB

Open AccessArticle

Synergetic Effect of Different Carrier Dynamics in Pm6:Y6:ITIC-M Ternary Cascade Energy Level System

by Zicha Li, Dandan Song, Zheng Xu, Bo Qiao, Suling Zhao, S. Wageh, Ahmed A Al-Ghamdi and Xiaomin Huo

Polymers 2021, 13(15), 2398; https://doi.org/10.3390/polym13152398 - 22 Jul 2021

Cited by 9 | Viewed by 5831

Abstract

Although reported ternary polymer solar cells have higher power conversion efficiency than binary polymers, the mechanism of exciton separation and charge transport in this complex ternary system is still unclear. Herein, based on PM6:Y6:ITIC-M ternary solar cells, we combine the technique of luminescence [...] Read more.

Although reported ternary polymer solar cells have higher power conversion efficiency than binary polymers, the mechanism of exciton separation and charge transport in this complex ternary system is still unclear. Herein, based on PM6:Y6:ITIC-M ternary solar cells, we combine the technique of luminescence spectroscopy, including electroluminescence (EL) and photoluminescence (PL) with photovoltaic measurements, to understand clearly the detailed roles of ITIC-M as the third component in the contribution of device performance. The results show that ITIC-M can form the alloy-like composite with Y6 but leave individual Y6 acceptor to conduct charge transfer with PM6 donor, which improves V_oc but decreases J_sc because of poor charge transfer capacity of ITIC-M. Meanwhile, the energy transfer from PM6 to ITIC-M exists in the active layers; small IE suppresses exciton dissociation. Deteriorating performance of solar cells demonstrates that, except for complementary absorption spectrum and suitable energy levels in PM6:Y6:ITIC-M system, the synergetic effects of carrier dynamics among different organic materials play an important role in influencing the performance of ternary solar cells. Full article

(This article belongs to the Topic Multiple Application for Novel and Advanced Materials)

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