Multiple Application for Novel and Advanced Materials

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Materials materials	3.1	5.8	2008	15.5 Days	CHF 2600
Coatings coatings	2.9	5.0	2011	13.7 Days	CHF 2600
Polymers polymers	4.7	8.0	2009	14.5 Days	CHF 2700
Fibers fibers	4.0	7.0	2013	33.6 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 4 | Viewed by 1923

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 1981

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 5 | Viewed by 1904

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 2347

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 1743

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 2896

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 3194

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 7 | Viewed by 2143

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 1945

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 9 | Viewed by 2788

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 9 | Viewed by 2032

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 3094

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 14 | Viewed by 3627

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 1969

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 10 | Viewed by 2551

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 3717

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 2309

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 10 | Viewed by 4484

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 9 | Viewed by 3974

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 2679

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 15 | Viewed by 2577

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 3066

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 2071

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 27 | Viewed by 2746

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 19 | Viewed by 4157

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 3 | Viewed by 2757

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 4 | Viewed by 2226

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 14 | Viewed by 2668

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 4 | Viewed by 2646

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 5 | Viewed by 2878

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 6 | Viewed by 3182

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 2832

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 6 | Viewed by 2360

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 9 | Viewed by 2337

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 3 | Viewed by 1555

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 2 | Viewed by 3304

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 9 | Viewed by 3639

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 2904

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 3712

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 14 | Viewed by 3385

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 7 | Viewed by 2711

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 4 | Viewed by 5347

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 3 | Viewed by 3095

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 7 | Viewed by 2296

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 29 | Viewed by 3571

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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