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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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32 pages, 7994 KiB  
Review
Recent Advancements in Smart Hydrogel-Based Materials in Cartilage Tissue Engineering
by Jakob Naranđa, Matej Bračič, Uroš Maver and Teodor Trojner
Materials 2025, 18(11), 2576; https://doi.org/10.3390/ma18112576 - 31 May 2025
Viewed by 1879
Abstract
Cartilage tissue engineering (CTE) is an advancing field focused on developing biomimetic scaffolds to overcome cartilage’s inherently limited self-repair capacity. Smart hydrogels (SHs) have gained prominence among the various scaffold materials due to their ability to modulate cellular behavior through tunable mechanical and [...] Read more.
Cartilage tissue engineering (CTE) is an advancing field focused on developing biomimetic scaffolds to overcome cartilage’s inherently limited self-repair capacity. Smart hydrogels (SHs) have gained prominence among the various scaffold materials due to their ability to modulate cellular behavior through tunable mechanical and biochemical properties. These hydrogels respond dynamically to external stimuli, offering precise control over biological processes and facilitating targeted tissue regeneration. Recent advances in fabrication technologies have enabled the design of SHs with sophisticated architecture, improved mechanical strength, and enhanced biointegration. Key features such as injectability, controlled biodegradability, and stimulus-dependent release of biomolecules make them particularly suitable for regenerative applications. The incorporation of nanoparticles further improves mechanical performance and delivery capability. In addition, shape memory and self-healing properties contribute to the scaffolds’ resilience and adaptability in dynamic physiological environments. An emerging innovation in this area is integrating artificial intelligence (AI) and omics-based approaches that enable high-resolution profiling of cellular responses to engineered hydrogels. These data-driven tools support the rational design and optimization of hydrogel systems and allow the development of more effective and personalized scaffolds. The convergence of smart hydrogel technologies with omics insights represents a transformative step in regenerative medicine and offers promising strategies for restoring cartilage function. Full article
(This article belongs to the Section Biomaterials)
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16 pages, 9841 KiB  
Article
Photochromic Sensors for Paper Marking
by Elżbieta Sąsiadek-Andrzejczak, Malwina Jaszczak-Kuligowska, Mariusz Dudek, Adam K. Puszkarz and Marek Kozicki
Materials 2025, 18(11), 2501; https://doi.org/10.3390/ma18112501 - 26 May 2025
Viewed by 380
Abstract
This study presents UV radiation sensors for use as paper marking. The sensors turn pink under exposure to UVA radiation and the color change is reversible. Additionally, a UV radiation retarder was applied to the sensor to delay the reaction and weaken the [...] Read more.
This study presents UV radiation sensors for use as paper marking. The sensors turn pink under exposure to UVA radiation and the color change is reversible. Additionally, a UV radiation retarder was applied to the sensor to delay the reaction and weaken the change in sensor color. The color changes of the sensors were analyzed depending on the absorbed dose of UVA radiation using reflectance spectrophotometry. Furthermore, the chemical analysis and surface morphology of the samples were performed using Raman Spectroscopy and Scanning Electron Microscopy, respectively. In addition, the structure of the sensors on the paper surface was assessed using X-ray Micro-Computed Tomography. Finally, possible potential applications for these types of sensors were presented, including marking, securing, and protecting against the counterfeiting of documents, paper packaging, and other paper products, and creating decorative elements, as well as measuring the 2D/3D dose distribution of UV radiation on paper products. Full article
(This article belongs to the Special Issue Synthesis and Characterization of Materials for Sensors)
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14 pages, 2100 KiB  
Article
Improved Bone Regeneration Using Biodegradable Polybutylene Succinate Artificial Scaffold with BMP-2 Protein in a Rabbit Model
by Giulio Edoardo Vigni, Mariano Licciardi, Lorenzo D’itri, Francesca Terracina, Sergio Scirè, Giuseppe Arrabito, Bruno Pignataro, Lawrence Camarda, Giovanni Cassata, Roberto Puleio, Lucio Di Silvestre and Luca Cicero
Materials 2025, 18(10), 2234; https://doi.org/10.3390/ma18102234 - 12 May 2025
Viewed by 453
Abstract
Extensive bone loss represents a great challenge for orthopedic and reconstructive surgery. On an in vivo rabbit model, the healing of two bone defects on a long bone, tibia, was studied. A polybutylene succinate (PBS) microfibrillar scaffold was implemented with BMP-2 protein and [...] Read more.
Extensive bone loss represents a great challenge for orthopedic and reconstructive surgery. On an in vivo rabbit model, the healing of two bone defects on a long bone, tibia, was studied. A polybutylene succinate (PBS) microfibrillar scaffold was implemented with BMP-2 protein and hydroxyapatite (HA) as potential osteogenic factors. The present study was carried out on 6 male New Zealand white (4–6 months old) rabbits in vivo model. One bone defect was created in each subject on the tibia. The controls were left to heal spontaneously while the study samples were treated with the polybutylene succinate (PBS) microfibrillar scaffolds doped with BMP-2 and HA. Histological and immunohistochemical analyses were performed after euthanasia at 3 and 6 months. The bone defect treated with the BMP-2 PBS scaffold shows, from 3 months, a significantly increased presence of activated osteoblasts with mineralized bone tissue deposition. This study confirms the great potential of PBS scaffolds in the clinical treatment of bone defects. Full article
(This article belongs to the Special Issue Advanced Materials for Bone Regeneration and Treatment)
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35 pages, 5269 KiB  
Article
The Quantum Transport of Dirac Fermions in Selected Graphene Nanosystems Away from the Charge Neutrality Point
by Adam Rycerz
Materials 2025, 18(9), 2036; https://doi.org/10.3390/ma18092036 - 29 Apr 2025
Viewed by 575
Abstract
The peculiar electronic properties of graphene, including the universal dc conductivity and the pseudodiffusive shot noise, are usually found in a small vicinity close to the charge neutrality point, away from which the electron’s effective mass raises, and nanostructures in graphene start to [...] Read more.
The peculiar electronic properties of graphene, including the universal dc conductivity and the pseudodiffusive shot noise, are usually found in a small vicinity close to the charge neutrality point, away from which the electron’s effective mass raises, and nanostructures in graphene start to behave similarly to familiar Sharvin contacts in semiconducting heterostructures. Recently, it was pointed out that as long as abrupt potential steps separate the sample area from the leads, some graphene-specific features can be identified relatively far from the charge neutrality point. These features include greater conductance reduction and shot noise enhancement compared to the standard Sharvin values. The purpose of this paper is twofold: First, we extend the previous analysis based on the effective Dirac equation, and derive the formulas that allow the calculation of the arbitrary charge transfer cumulant for doped graphene. Second, the results of the analytic considerations are compared with numerical simulations of quantum transport on the honeycomb lattice for selected nanosystems for which considerations starting from the Dirac equation cannot be directly adapted. For a wedge-shaped constriction with zigzag edges, the transport characteristics can be tuned from graphene-specific (sub-Sharvin) values to standard Sharvin values by varying the electrostatic potential profile in the narrowest section. A similar scenario is followed by the half-Corbino disk. In contrast, a circular quantum dot with two narrow openings showing a mixed behavior appears: the conductance is close to the Sharvin value, while the Fano factor approaches the value characterizing the symmetric chaotic cavity. Carving a hole in the quantum dot to eliminate direct trajectories between the openings reduces the conductance to sub-Sharvin value, but the Fano factor is unaffected. Our results suggest that experimental attempts to verify the predictions for the sub-Sharvin transport regime should focus on systems with relatively wide openings, where the scattering at the sample edges is insignificant next to the scattering at the sample–lead interfaces. Full article
(This article belongs to the Special Issue Quantum Transport in Novel 2D Materials and Structures)
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15 pages, 3554 KiB  
Article
Study of ZrO2 Gate Dielectric with Thin SiO2 Interfacial Layer in 4H-SiC Trench MOS Capacitors
by Qimin Huang, Yunduo Guo, Anfeng Wang, Zhaopeng Bai, Lin Gu, Zhenyu Wang, Chengxi Ding, Yi Shen, Hongping Ma and Qingchun Zhang
Materials 2025, 18(8), 1741; https://doi.org/10.3390/ma18081741 - 10 Apr 2025
Viewed by 613
Abstract
The transition of SiC MOSFET structure from planar to trench-based architectures requires the optimization of gate dielectric layers to improve device performance. This study utilizes a range of characterization techniques to explore the interfacial properties of ZrO2 and SiO2/ZrO2 [...] Read more.
The transition of SiC MOSFET structure from planar to trench-based architectures requires the optimization of gate dielectric layers to improve device performance. This study utilizes a range of characterization techniques to explore the interfacial properties of ZrO2 and SiO2/ZrO2 gate dielectric films, grown via atomic layer deposition (ALD) in SiC epitaxial trench structures to assess their performance and suitability for device applications. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements showed the deposition of smooth film morphologies with roughness below 1 nm for both ZrO2 and SiO2/ZrO2 gate dielectrics, while SE measurements revealed comparable physical thicknesses of 40.73 nm for ZrO2 and 41.55 nm for SiO2/ZrO2. X-ray photoelectron spectroscopy (XPS) shows that in SiO2/ZrO2 thin films, the binding energies of Zr 3d5/2 and Zr 3d3/2 peaks shift upward compared to pure ZrO2. Electrical characterization showed an enhancement of EBR (3.76 to 5.78 MV·cm−1) and a decrease of ION_EBR (1.94 to 2.09 × 10−3 A·cm−2) for the SiO2/ZrO2 stacks. Conduction mechanism analysis identified suppressed Schottky emission in the stacked film. This indicates that the incorporation of a thin SiO2 layer effectively mitigates the small bandgap offset, enhances the breakdown electric field, reduces leakage current, and improves device performance. Full article
(This article belongs to the Special Issue Feature Papers in Materials Physics (2nd Edition))
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14 pages, 8353 KiB  
Article
Design and Characterization of an Equibiaxial Multi-Electrode Dielectric Elastomer Actuator
by Simon Holzer, Bhawnath Tiwari, Stefania Konstantinidi, Yoan Civet and Yves Perriard
Materials 2025, 18(8), 1693; https://doi.org/10.3390/ma18081693 - 8 Apr 2025
Viewed by 403
Abstract
With the ongoing journey of automation advancements and a trend towards miniaturization, the choice of actuator plays a crucial role. Over recent years, soft actuators have demonstrated their usefulness in various applications, especially where light weight and high strain are required. Dielectric elastomer [...] Read more.
With the ongoing journey of automation advancements and a trend towards miniaturization, the choice of actuator plays a crucial role. Over recent years, soft actuators have demonstrated their usefulness in various applications, especially where light weight and high strain are required. Dielectric elastomer actuators (DEAs) are a class of soft actuators that provide high-strain actuation possibilities in applications like biomedicine, logistics, or consumer electronics. A variety of work featuring DEAs for actuation has been carried out in recent years, but a single work detailing the design conception, fabrication, modeling and experimental validation is lacking, especially in the context of achieving high strains with the integration of multiple electrodes and their interaction. This work discusses these issues with an equibiaxial DEA, enabling optimized equibiaxial strain patterns due to full use of the available actuation area. The developed DEA can achieve an equibiaxial strain of 12.75% for actuation at 60 V μm−1 over an active area of 7 cm2 which is an improvement of 1.3 times compared to traditional dot actuators. These properties position the device as a promising alternative for various applications like cell cultures or microassembly and provide an advantage of optimized use of passive regions within the actuator. Full article
(This article belongs to the Special Issue Electroactive Polymers: Fundamentals and Applications)
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19 pages, 5369 KiB  
Article
Interactions of Terahertz Photons with Phonons of Two-Dimensional van der Waals MoS2/WSe2/MoS2 Heterostructures and Thermal Responses
by Jingwen Huang, Ningsheng Xu, Yumao Wu, Xue Ran, Yue Fang, Hongjia Zhu, Weiliang Wang, Huanjun Chen and Shaozhi Deng
Materials 2025, 18(7), 1665; https://doi.org/10.3390/ma18071665 - 4 Apr 2025
Viewed by 767
Abstract
The interaction between terahertz (THz) photons and phonons of materials is crucial for the development of THz photonics. In this work, typical two-dimensional (2D) van der Waals (vdW) transition metal chalcogenide (TMD) layers and heterostructures are used in THz time-domain spectroscopy (TDS) measurements, [...] Read more.
The interaction between terahertz (THz) photons and phonons of materials is crucial for the development of THz photonics. In this work, typical two-dimensional (2D) van der Waals (vdW) transition metal chalcogenide (TMD) layers and heterostructures are used in THz time-domain spectroscopy (TDS) measurements, low-wavenumber Raman spectroscopy measurements, calculation of 2D materials’ phonon spectra, and theoretical analysis of thermal responses. The TDS results reveal strong absorption of THz photons in the frequency range of 2.5–10 THz. The low-wavenumber Raman spectra show the phonon vibration characteristics and are used to establish phonon energy bands. We also set up a computational simulation model for thermal responses. The temperature increases and distributions in the individual layers and their heterostructures are calculated, showing that THz photon absorption results in significant increases in temperature and differences in the heterostructures. These give rise to interesting photothermal effects, including the Seebeck effect, resulting in voltages across the heterostructures. These findings provide valuable guidance for the potential optoelectronic application of the 2D vdW heterostructures. Full article
(This article belongs to the Special Issue Terahertz Vibrational Spectroscopy in Advanced Materials)
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17 pages, 3636 KiB  
Article
DFT Investigation of a Direct Z-Scheme Photocatalyst for Overall Water Splitting: Janus Ga2SSe/Bi2O3 Van Der Waals Heterojunction
by Fan Yang, Pascal Boulet and Marie-Christine Record
Materials 2025, 18(7), 1648; https://doi.org/10.3390/ma18071648 - 3 Apr 2025
Viewed by 656
Abstract
Constructing van der Waals heterojunctions with excellent properties has attracted considerable attention in the field of photocatalytic water splitting. In this study, four patterns, coined A, B, C, and D of Janus Ga2SSe/Bi2O3 van der Waals (vdW) heterojunctions [...] Read more.
Constructing van der Waals heterojunctions with excellent properties has attracted considerable attention in the field of photocatalytic water splitting. In this study, four patterns, coined A, B, C, and D of Janus Ga2SSe/Bi2O3 van der Waals (vdW) heterojunctions with different stacking modes, were investigated using first-principles calculations. Their stability, electronic structure, and optical properties were analyzed in detail. Among these, patterns A and C heterojunctions demonstrate stable behavior and operate as direct Z-scheme photocatalysts, exhibiting band gaps of 1.83 eV and 1.62 eV. In addition, the suitable band edge positions make them effective for photocatalytic water decomposition. The built-in electric field across the heterojunction interface effectively inhibits electron-hole recombination, thereby improving the photocatalytic efficiency. The optical absorption coefficients show that patterns A and C heterojunctions exhibit higher light absorption intensity than Ga2SSe and Bi2O3 monolayers, spanning from the ultraviolet to visible range. Their corrected solar-to-hydrogen (STH) efficiencies are 13.60% and 12.08%, respectively. The application of hydrostatic pressure and biaxial tensile strain demonstrate distinct effects on photocatalytic performance: hydrostatic pressure preferentially enhances the hydrogen evolution reaction (HER), while biaxial tensile strain primarily improves the oxygen evolution reaction (OER). Furthermore, the heterojunctions exhibited enhanced optical absorption across the UV-visible spectrum with increasing hydrostatic pressure. Notably, a 1% tensile strain results in an improvement in visible light absorption efficiency. These results demonstrate that Ga2SSe/Bi2O3 heterojunctions hold great promise as direct Z-scheme photocatalysts for overall water splitting. Full article
(This article belongs to the Special Issue Hierarchically Structured Materials for Photocatalysis, Electrocatalysis and Photoelectrocatalysis)
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15 pages, 6248 KiB  
Article
Precursor-Derived Mo2C/SiC Composites with a Two-Dimensional Sheet Structure for Electromagnetic Wave Absorption
by Yang Li, Wen Yang, Jipeng Zhang, Yongzhao Hou, Guangwu Wen, Guodong Xin, Meixian Jiang and Yongqiang Ma
Materials 2025, 18(7), 1573; https://doi.org/10.3390/ma18071573 - 31 Mar 2025
Viewed by 397
Abstract
Precursor-derived silicon carbide (SiC) ceramics have been widely used as absorbing materials, but the residual carbon sink produced by ceramicization limits their application under high-temperature and oxygen-containing conditions, such as the nozzle or jet vane of high-speed aircraft. In this paper, a novel [...] Read more.
Precursor-derived silicon carbide (SiC) ceramics have been widely used as absorbing materials, but the residual carbon sink produced by ceramicization limits their application under high-temperature and oxygen-containing conditions, such as the nozzle or jet vane of high-speed aircraft. In this paper, a novel molybdenum carbide/silicon carbide (Mo2C/SiC) microwave-absorbing ceramic with a two-dimensional sheet structure was obtained through the pyrolysis of polycarbosilane-coated molybdenum sulfide (PCS@MoS2). The results indicate that addition of an appropriate amount of MoS2 can react with the free carbon generated during the pyrolysis of PCS, thereby reducing the material’s carbon content and forming Mo2C. Concurrently, the layered structural characteristics of MoS2 are utilized to create a two-dimensional composite structure within the material, which enhances the material’s absorption vastly. The as-prepared Mo2C/SiC ceramics sintered at 1300 °C exhibit a minimum reflection loss (RLmin) of −46.49 dB at 8.96 GHz with a thickness of 2.6 mm. Additionally, the effective absorption bandwidth (EAB) of Mo2C/SiC spans the entire X-band (8–12 GHz) due to the combined effect of multiple loss mechanisms. Full article
(This article belongs to the Section Advanced and Functional Ceramics and Glasses)
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10 pages, 3175 KiB  
Article
Electric Field-Defined Superlattices in Bilayer Graphene: Formation of Topological Bands in Two Dimensions
by Włodzimierz Jaskólski
Materials 2025, 18(7), 1521; https://doi.org/10.3390/ma18071521 - 28 Mar 2025
Viewed by 499
Abstract
An electric field applied to the Bernal-stacked bilayer graphene opens an energy gap; its reversal in some regions creates domain walls and leads to the appearance of one-dimensional chiral gapless states localized at the walls. Here, we investigate the energy structure of bilayer [...] Read more.
An electric field applied to the Bernal-stacked bilayer graphene opens an energy gap; its reversal in some regions creates domain walls and leads to the appearance of one-dimensional chiral gapless states localized at the walls. Here, we investigate the energy structure of bilayer graphene with superlattice potential defined by an external electric field. The calculations are performed within an atomistic π-electron tight-binding approximation. We study one-dimensional and two-dimensional superlattices formed by arrays of electric-field walls in the zigzag and armchair directions and investigate different field polarizations. Chiral gapless states discretize due to the superlattice potential and transform into minibands in the energy gap. As the main result, we show that the minibands can cross at the Fermi level for some field polarizations. This leads to a new kind of two-dimensional gapless states of topological character that form Dirac-like cones at the crossing points. This also has application potential: changing the field polarization can close the energy gap and change the character of the superlattice from semiconducting to metallic. Full article
(This article belongs to the Special Issue Quantum Transport in Novel 2D Materials and Structures)
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28 pages, 4096 KiB  
Article
Spontaneous and Piezo Polarization Versus Polar Surfaces: Fundamentals and Ab Initio Calculations
by Pawel Strak, Pawel Kempisty, Konrad Sakowski, Jacek Piechota, Izabella Grzegory, Eva Monroy, Agata Kaminska and Stanislaw Krukowski
Materials 2025, 18(7), 1489; https://doi.org/10.3390/ma18071489 - 26 Mar 2025
Cited by 1 | Viewed by 484
Abstract
In this study, the fundamental properties of spontaneous and piezo polarization and surface polarity were defined. It was demonstrated that the Landau definition of polarization as a dipole density could be used in infinite systems. Differences between bulk polarization and surface polarity were [...] Read more.
In this study, the fundamental properties of spontaneous and piezo polarization and surface polarity were defined. It was demonstrated that the Landau definition of polarization as a dipole density could be used in infinite systems. Differences between bulk polarization and surface polarity were distinguished, thus creating a clear identification of both components. This identification is in agreement with numerous experimental data—red shift presence and absence for wurtzite and zinc blende multiquantum wells (MQWs), respectively. A local model of spontaneous polarization was created and used to calculate spontaneous polarization as electric dipole density. The proposed local model correctly predicted the c-axis spontaneous polarization values of nitride wurtzite semiconductors. In addition, the model’s results are in accordance with a polarization equal to zero for the zinc blende lattice. The spontaneous polarization values obtained for all wurtzite III nitrides are in basic agreement with earlier calculations using the Berry phase. Ab initio calculations of wurtzite nitride superlattices in Heyd–Scuseria–Ernzerhof (HSE) approximation were performed to derive polarization-induced fields in coherently strained lattices, showing good agreement with the polarization values. Strained superlattice data were used to determine the piezoelectric parameters of wurtzite nitrides, obtaining values that are in basic agreement with earlier data. Zinc blende superlattices were also modeled using ab initio HSE calculations, showing results that are in agreement with the absence of polarization in all nitrides in zinc blende symmetry. Full article
(This article belongs to the Special Issue Advances in Density Functional Theory (DFT) Studies of Solids (Second Volume))
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17 pages, 7854 KiB  
Article
Understanding Polysiloxane Polymer to Amorphous SiOC Conversion During Pyrolysis Through ReaxFF Simulation
by Kathy Lu and Harrison Chaney
Materials 2025, 18(7), 1412; https://doi.org/10.3390/ma18071412 - 22 Mar 2025
Viewed by 457
Abstract
A significant challenge during the polymer-to-ceramic pyrolysis conversion is to understand the polymer-to-ceramic atomic evolution and correlate the composition changes with the precursor molecular structures, pyrolysis conditions, and resulting ceramic characteristics. In this study, a Reactive Force Field (ReaxFF) simulation approach has been [...] Read more.
A significant challenge during the polymer-to-ceramic pyrolysis conversion is to understand the polymer-to-ceramic atomic evolution and correlate the composition changes with the precursor molecular structures, pyrolysis conditions, and resulting ceramic characteristics. In this study, a Reactive Force Field (ReaxFF) simulation approach has been used to simulate silicon oxycarbide (SiOC) ceramic formation from four different polysiloxane precursors. For the first time, we show atomically that pyrolysis time and temperature proportionally impact the new Si-O rich and C rich cluster sizes as well as the composition separation of Si-O from C. Polymer side groups have a more complex effect on the Si-O and C cluster separation and growth, with ethyl group leading to the most Si-O cluster separation and phenyl group leading to the most C cluster separation. We also demonstrate never-before correlations of gas release with polymer molecular structures and functional groups. CH4, C2H6, C2H4, and H2 are preferentially released from the pyrolyzing systems. The sequence is determined by the polymer molecular structures. This work is the first to atomically illustrate the innate correlations between the polymer precursors and pyrolyzed ceramics. Full article
(This article belongs to the Special Issue Structural, Thermal, Electrical, and Electrochemical Properties of Novel Ceramics)
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18 pages, 74287 KiB  
Article
Graining and Texturing of Metal Surfaces by Picosecond Laser Treatment
by Carmelo Corsaro, Fortunato Neri, Paolo Maria Ossi, Domenico Bonanno, Priscilla Pelleriti and Enza Fazio
Materials 2025, 18(7), 1398; https://doi.org/10.3390/ma18071398 - 21 Mar 2025
Viewed by 657
Abstract
Different approaches have been proposed to control the tribological behavior of materials under different conformal and non-conformal contact conditions with influenced surface texturing. The ever-increasing demand to improve material friction, erosion wear, and adhesion bond strength of coatings is a major concern for [...] Read more.
Different approaches have been proposed to control the tribological behavior of materials under different conformal and non-conformal contact conditions with influenced surface texturing. The ever-increasing demand to improve material friction, erosion wear, and adhesion bond strength of coatings is a major concern for the contact interface of surfaces. Laser texturing is considered a promising approach to tuning materials’ tribological properties. The latter are strongly influenced by the texture density and shape imprinted on the engineered materials and vary in dry or lubricating conditions. In this work, the physicochemical properties of picosecond laser-textured surfaces of metallic materials have been systematically analyzed. Specifically, the wettability character of laser-textured materials was correlated with their morphological/compositional features. Full article
(This article belongs to the Section Materials Physics)
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17 pages, 3853 KiB  
Article
Analysis of the Structural, Chemical, and Mechanical Characteristics of Polyurethane Foam Infused with Waste from Thermal Processing
by Anna Magiera, Monika Kuźnia and Wojciech Jerzak
Materials 2025, 18(6), 1327; https://doi.org/10.3390/ma18061327 - 17 Mar 2025
Cited by 1 | Viewed by 368
Abstract
The continuous generation of agricultural, industrial, and urban waste necessitates effective waste management strategies. One promising approach is incorporating these residues as fillers in polymer composites. This study investigated the influence of coal processing-derived fillers, specifically microspheres and fluidized-bed combustion fly ash, on [...] Read more.
The continuous generation of agricultural, industrial, and urban waste necessitates effective waste management strategies. One promising approach is incorporating these residues as fillers in polymer composites. This study investigated the influence of coal processing-derived fillers, specifically microspheres and fluidized-bed combustion fly ash, on the structure and properties of composite rigid polyurethane foam. Polyurethane foams were produced through manual mixing and casting, with composite foams containing a combination of 5% microspheres and 5–15% fly ash by weight. The analysis of the samples investigated their structural, thermal, and mechanical properties. The samples consistently displayed predominantly pentagonal, regularly shaped cells. Infrared spectroscopy revealed no observable chemical bonding between the matrix and filler materials. Mechanical analysis was performed to evaluate the materials’ characteristics, revealing significant variations in compressive strength and Young’s modulus values. The results indicate that the addition of fillers did not impact the cellular and chemical composition of the polyurethane matrix. Furthermore, the composite material specimens were subjected to accelerated aging in a laboratory dryer and outdoor exposure in order to assess their thermal stability. This analysis revealed notable alterations in both the cellular composition and mechanical properties of the composite foam materials. Full article
(This article belongs to the Special Issue Research on Thermal Stability and Degradation of Polymers and Their Potential Use in a Circular Economy Development)
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17 pages, 3101 KiB  
Article
Removal of Per- and Polyfluoroalkyl Substances Using Commercially Available Sorbents
by Zhiming Zhang, Sevda Joudiazar, Anshuman Satpathy, Eustace Fernando, Roxana Rahmati, Junchul Kim, Giacomo de Falco, Rupali Datta and Dibyendu Sarkar
Materials 2025, 18(6), 1299; https://doi.org/10.3390/ma18061299 - 15 Mar 2025
Viewed by 2093
Abstract
Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants of growing environmental and human health concern, widely detected across various environmental compartments. Effective remediation strategies are essential to mitigate their widespread impacts. This study compared the performance of two types of commercially available [...] Read more.
Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants of growing environmental and human health concern, widely detected across various environmental compartments. Effective remediation strategies are essential to mitigate their widespread impacts. This study compared the performance of two types of commercially available sorbent materials, granular activated carbon (GAC, Filtrasorb-400) and organoclays (OC-200, and modified organoclays Fluoro-sorb-100 and Fluoro-sorb-200) for the removal of three representative PFAS compounds: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctane sulfonic acid (PFOS) from water. Both organoclays and modified organoclays outperformed GAC, likely due to electrostatic interactions between the anionic PFAS compounds and the cationic functional groups of the modified organoclays. A pseudo-second-order kinetic model best described the rapid sorption kinetics of PFOA, PFNA, and PFOS. For PFOA, OC-200 demonstrated the highest adsorption capacities (qmax = 47.17 µg/g). For PFNA and PFOS, Fluoro-sorb-100 was the most effective sorbent, with qmax values at 99.01 µg/g and 65.79 µg/g, respectively. Desorption studies indicated that the sorption of the three PFAS compounds on these commercially available sorbents was largely irreversible. This study highlights the effectiveness and sorption capacities of different types of commercial sorbents for PFAS removal and offers valuable insights into the selection of reactive media for PFAS removal from water under environmentally relevant conditions. Full article
(This article belongs to the Special Issue Advanced Nanoporous and Mesoporous Materials)
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13 pages, 3445 KiB  
Article
Evaluating the Role of Unit Cell Multiplicity in the Acoustic Response of Phononic Crystals Using Laser-Plasma Sound Sources
by Emmanouil Kaniolakis Kaloudis, Konstantinos Kaleris, Nikos Aravantinos-Zafiris, Michael Sigalas, Dionysios T. G. Katerelos, Vasilis Dimitriou, Makis Bakarezos, Michael Tatarakis and Nektarios A. Papadogiannis
Materials 2025, 18(6), 1251; https://doi.org/10.3390/ma18061251 - 12 Mar 2025
Viewed by 681
Abstract
Acoustic metamaterials and phononic crystals are progressively consolidating as an important technology that is expected to significantly impact the science and industry of acoustics in the coming years. In this work, the impact of unit cell multiplicity on the spectral features of the [...] Read more.
Acoustic metamaterials and phononic crystals are progressively consolidating as an important technology that is expected to significantly impact the science and industry of acoustics in the coming years. In this work, the impact of unit cell multiplicity on the spectral features of the acoustic response of phononic crystals is systematically studied using the recently demonstrated laser-plasma sound source characterization method. Specifically, by exploiting the advantages of this method, the impact of the number of repeated unit cells on the depth of the phononic band gaps and the passband spectral features across the entire audible range is demonstrated. These experimental findings are supported by specially developed computational simulations accounting for the precise structural characteristics of the studied phononic crystals and are analysed to provide a phenomenological understanding of the underlying physical mechanism. It is shown that by increasing the unit cell multiplicity, the bandgaps deepen and the number of resonant peaks in the crystal transmission zones increases. The resonant mode shapes are computationally investigated and interpreted in terms of spherical harmonics. This study highlights the tunability and design flexibility of acoustic components using phononic crystals, opening new paths towards applications in the fields of sound control and noise insulation. Full article
(This article belongs to the Special Issue Advances in Modelling and Simulation of Materials in Applied Sciences)
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10 pages, 2639 KiB  
Communication
A High-Performance All-Carbon Diamond Pixel Solar-Blind Detector with In Situ Converted Graphene Electrodes
by Mingxin Jiang, Zhenglin Jia, Mengting Qiu, Xingqiao Chen, Jiayi Cai, Mingyang Yang, Yi Shen, Chaoping Liu, Kuan W. A. Chee, Nan Jiang, Kazuhito Nishimura, Qingning Li, Qilong Yuan and He Li
Materials 2025, 18(6), 1222; https://doi.org/10.3390/ma18061222 - 10 Mar 2025
Viewed by 729
Abstract
Solar-blind ultraviolet detectors, known for their low background noise and high sensitivity, have garnered significant attention in various applications such as space communications, ozone layer monitoring, guidance applications, and flame detection. Pixel photodetectors, as the cornerstone of imaging technology in this field, have [...] Read more.
Solar-blind ultraviolet detectors, known for their low background noise and high sensitivity, have garnered significant attention in various applications such as space communications, ozone layer monitoring, guidance applications, and flame detection. Pixel photodetectors, as the cornerstone of imaging technology in this field, have become a focal point of research in recent years. In this work, a solar-blind photodetector with a 6 × 6 planar pixel array was fabricated on single-crystal diamond substrate, utilizing in situ conversed graphene electrodes. The graphene electrodes achieved exceptional Ohmic contact with the diamond surface, boasting a remarkably low specific contact resistance of 6.73 × 10−5 Ω·cm2. The diamond pixel detector exhibited high performance consistency with an ultra-low dark current ranging from 10−11 to 10−12 A and a photocurrent of 10−8~10−9 A under 222 nm illumination with a bias of 10 V. This work not only demonstrates the feasibility of fabricating all-carbon solar-blind photodetectors on diamond but also highlights their potential for achieving high spatial resolution in solar-blind image detection. Full article
(This article belongs to the Section Electronic Materials)
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13 pages, 1891 KiB  
Article
Microstructure-Based Magneto-Mechanical Modeling of Magnetorheological Elastomer Composites: A Comparable Analysis of Dipole and Maxwell Methods
by Shengwei Feng and Lizhi Sun
Materials 2025, 18(5), 1187; https://doi.org/10.3390/ma18051187 - 6 Mar 2025
Cited by 1 | Viewed by 749
Abstract
Magnetorheological elastomers (MREs) are smart composite materials with tunable mechanical properties by ferromagnetic particle interactions. This study applied the microstructure-based dipole and Maxwell methods to evaluate the magneto-mechanical coupling and magnetostrictive responses of MREs, focusing on various particle distributions. The finite element modeling [...] Read more.
Magnetorheological elastomers (MREs) are smart composite materials with tunable mechanical properties by ferromagnetic particle interactions. This study applied the microstructure-based dipole and Maxwell methods to evaluate the magneto-mechanical coupling and magnetostrictive responses of MREs, focusing on various particle distributions. The finite element modeling of representative volume elements with fixed volume fractions revealed that the straight chain microstructure exhibits the most significant magnetostrictive effect due to its low initial shear stiffness and significant magnetic force contributions. For particle separations exceeding three radii, the dipole and Maxwell methods yield consistent results for vertically or horizontally aligned particles. For particle separations greater than three radii, the dipole and Maxwell methods produce consistent results for vertically and horizontally aligned particles. However, discrepancies emerge for angled configurations and complex microstructures, with the largest deviation observed in the hexagonal particle distribution, where the two methods differ by approximately 27%. These findings highlight the importance of selecting appropriate modeling methods for optimizing MRE performance. Since anisotropic MREs with straight-chain alignments are the most widely used, our results confirm that the dipole method offers an efficient alternative to the Maxwell method for simulating these structures. Full article
(This article belongs to the Special Issue Smart Soft Materials: From Design to Applications)
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18 pages, 7417 KiB  
Article
An Efficient Optimization Method for Large-Solution Space Electromagnetic Automatic Design
by Lingyan He, Fengling Peng and Xing Chen
Materials 2025, 18(5), 1159; https://doi.org/10.3390/ma18051159 - 5 Mar 2025
Viewed by 698
Abstract
In the field of electromagnetic design, it is sometimes necessary to search for the optimal design solution (i.e., the optimal solution) within a large solution space to complete the optimization. However, traditional optimization methods are not only slow in searching for the solution [...] Read more.
In the field of electromagnetic design, it is sometimes necessary to search for the optimal design solution (i.e., the optimal solution) within a large solution space to complete the optimization. However, traditional optimization methods are not only slow in searching for the solution space but are also prone to becoming trapped in local optima, leading to optimization failure. This paper proposes a dual-population genetic algorithm to quickly find the optimal solution for electromagnetic optimization problems in large solution spaces. The method involves two populations: the first population uses the powerful dynamic decision-making ability of reinforcement learning to adjust the crossover probability, making the optimization process more stable and enhancing the global optimization capability of the algorithm. The second population accelerates the convergence speed of the algorithm by employing a “leader dominance” mechanism, allowing the population to quickly approach the optimal solution. The two populations are integrated through an immigration operator, improving optimization efficiency. The effectiveness of the proposed method is demonstrated through the optimization design of an electromagnetic metasurface material. Furthermore, the method designed in this paper is not limited to the electromagnetic field and has practical value in other engineering optimization areas, such as vehicle routing optimization, energy system optimization, and fluid dynamics optimization, etc. Full article
(This article belongs to the Special Issue Metamaterials and Metasurfaces: From Materials to Applications)
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16 pages, 6479 KiB  
Article
Vat Photopolymerization of CeO2-Incorporated Hydrogel Scaffolds with Antimicrobial Efficacy
by Nelly Aimelyne Mpuhwe, Gyu-Nam Kim and Young-Hag Koh
Materials 2025, 18(5), 1125; https://doi.org/10.3390/ma18051125 - 2 Mar 2025
Viewed by 1039
Abstract
We herein demonstrate the utility of gelatin methacryloyl (GelMA)/poly(ethylene glycol) diacrylate (PEGDA)–cerium oxide (CeO2) hydrogel inks for manufacturing hydrogel scaffolds with antimicrobial efficacy by vat photopolymerization. For uniform blending with GelMA/PEGDA hydrogels, CeO2 nanoparticles with a round shape were synthesized [...] Read more.
We herein demonstrate the utility of gelatin methacryloyl (GelMA)/poly(ethylene glycol) diacrylate (PEGDA)–cerium oxide (CeO2) hydrogel inks for manufacturing hydrogel scaffolds with antimicrobial efficacy by vat photopolymerization. For uniform blending with GelMA/PEGDA hydrogels, CeO2 nanoparticles with a round shape were synthesized by the precipitation method coupled with calculation at 600 °C. In addition, they had highly crystalline phases and the desired chemical structures (oxidation states of Ce3+ and Ce4+) required for outstanding antimicrobial efficacy. A range of GelMA/PEGDA-CeO2 hydrogel scaffolds with different CeO2 contents (0% w/v, 0.1% w/v, 0.5% w/v, 1% w/v, and 5% w/v with respect to distilled water content) were manufactured. The photopolymerization behavior, mechanical properties, and biological properties (swelling and biodegradation behaviors) of hydrogel scaffolds were characterized to optimize the CeO2 content. GelMA/PEGDA-CeO2 hydrogel scaffolds produced with the highest CeO2 content (5% w/v) showed reasonable mechanical properties (compressive strength = 0.56 ± 0.09 MPa and compressive modulus = 0.19 ± 0.03 MPa), a high swelling ratio (1063.3 ± 10.9%), and the desired biodegradation rate (remaining weight after 28 days = 39.6 ± 2.3%). Furthermore, they showed outstanding antimicrobial efficacy (the number of colony-forming units = 76 ± 44.6 (×103)). In addition, macroporous GelMA/PEGDA-CeO2 hydrogel scaffolds with tightly controlled porous structures could be manufactured by vat photopolymerization. Full article
(This article belongs to the Section Biomaterials)
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16 pages, 5953 KiB  
Article
Memory Devices with HfO2 Charge-Trapping and TiO2 Channel Layers: Fabrication via Remote and Direct Plasma Atomic Layer Deposition and Comparative Performance Evaluation
by Inkook Hwang, Jiwon Kim, Joungho Lee, Yeonwoong Jung and Changbun Yoon
Materials 2025, 18(5), 948; https://doi.org/10.3390/ma18050948 - 21 Feb 2025
Cited by 1 | Viewed by 796
Abstract
With the improvement of integration levels to several nanometers or less, semiconductor leakage current has become an important issue, and oxide-based semiconductors, which have replaced Si-based channel layer semiconductors, have attracted attention. Herein, we fabricated capacitors with a metal–insulator–semiconductor–metal structure using HfO2 [...] Read more.
With the improvement of integration levels to several nanometers or less, semiconductor leakage current has become an important issue, and oxide-based semiconductors, which have replaced Si-based channel layer semiconductors, have attracted attention. Herein, we fabricated capacitors with a metal–insulator–semiconductor–metal structure using HfO2 thin films deposited at 240 °C and TiO2 thin films deposited at 300 °C via remote plasma (RP) and direct plasma (DP) atomic layer deposition and analyzed the effects of the charge-trapping and semiconducting properties of these films. Charge-trapping memory (CTM) devices with HfO2 (charge-trapping layer) and TiO2 (semiconductor) films were fabricated and characterized in terms of their memory properties. Al2O3 thin films were used as blocking and tunneling layers to prevent the leakage of charges stored in the charge-trapping layer. For the TiO2 layer, the heat-treatment temperature was optimized to obtain an anatase phase with optimal semiconductor properties. The memory characteristics of the RP HfO2–TiO2 CTM devices were superior to those of the DP HfO2–TiO2 CTM devices. This result was ascribed to the decrease in the extent of damage and contamination observed when the plasma was spaced apart from the deposited HfO2 and TiO2 layers (i.e., in the case of RP deposition) and the reduction in the concentration of oxygen vacancies at the interface and in the films. Full article
(This article belongs to the Special Issue Metal Oxide Semiconductors: Synthesis, Structure, and Applications)
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19 pages, 10708 KiB  
Article
Evaluation of the Influence of Primary and Secondary Crystal Orientations and Selected Structural Characteristics on Creep Resistance in Single-Crystal Nickel-Based Turbine Blades
by Kamil Gancarczyk, Robert Albrecht, Paweł Sułkowicz, Mirosław Szala and Mariusz Walczak
Materials 2025, 18(5), 919; https://doi.org/10.3390/ma18050919 - 20 Feb 2025
Cited by 2 | Viewed by 692
Abstract
This study evaluates the perfection of the crystal structure of single-crystal turbine blade castings made from the CMSX-4 nickel superalloy. The analysis included primary and secondary crystal orientation measurements using the Ω-scan method and the novel OD-EFG X-ray diffractometer. The selected microstructural parameters [...] Read more.
This study evaluates the perfection of the crystal structure of single-crystal turbine blade castings made from the CMSX-4 nickel superalloy. The analysis included primary and secondary crystal orientation measurements using the Ω-scan method and the novel OD-EFG X-ray diffractometer. The selected microstructural parameters of the single crystals were also analyzed, including the assessment of stereological parameters and the degree of porosity. A creep test was performed according to standard procedures and under conditions simulating real operational environments. The model single-crystal turbine blades were manufactured using the Bridgman–Stockbarger method, with variable withdrawal rates of 1 and 3 mm/min. Heat treatment of the single-crystal castings involved solution treatment followed by double aging. The evaluation of structural perfection was carried out in three states: as-cast, after solution heat treatment, and after double aging. The crystallographic orientation of the blades was determined on both the airfoil and the root part. The study determined how crystallographic orientation and microstructural parameters influence the creep resistance of the castings. It was found that in the as-cast condition, the greatest influence on high creep strength has a small deviation of the primary and constant value of secondary crystal orientation along the height of the blade casting. After heat treatment, the highest creep resistance was obtained for the blade manufactured at a withdrawal rate at 1 mm/min. Full article
(This article belongs to the Section Metals and Alloys)
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51 pages, 17258 KiB  
Review
A Review of Simulation Tools Utilization for the Process of Laser Powder Bed Fusion
by Ľuboš Kaščák, Ján Varga, Jana Bidulská, Róbert Bidulský and Tibor Kvačkaj
Materials 2025, 18(4), 895; https://doi.org/10.3390/ma18040895 - 18 Feb 2025
Cited by 2 | Viewed by 1198
Abstract
This review describes the process of metal additive manufacturing and focuses on the possibility of correlated input parameters that are important for this process. The correlation of individual parameters in the metal additive manufacturing process is considered using simulation tools that allow the [...] Read more.
This review describes the process of metal additive manufacturing and focuses on the possibility of correlated input parameters that are important for this process. The correlation of individual parameters in the metal additive manufacturing process is considered using simulation tools that allow the prediction of various defects, thus making the real production process more efficient, especially in terms of time and costs. Special attention is paid to multiple applications using these simulation tools as an initial analysis to determine the material’s behavior when defining various input factors, including the results obtained. Based on this, further procedures were implemented, including real production parts. This review also points out the range of possible variations that simulation tools have, which helps to effectively predict material defects and determine the volume of consumed material, supports construction risk, and other information necessary to obtain a quality part in the production process. From the overview of the application of simulation tools in this process, it was found that the correlation between theoretical knowledge and the definition of individual process parameters and other variables are related and are of fundamental importance for achieving the final part with the required properties. In terms of some specific findings, it can be noted that simulation tools identify adverse phenomena occurring in the production processes and allow manufacturers to test the validity of the proposed conceptual and model solutions without making actual changes in the production system, and they have the measurable impact on the design and production of quality parts. Full article
(This article belongs to the Special Issue Plastic Deformation and Mechanical Behavior of Metallic Materials)
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13 pages, 3773 KiB  
Article
Transition-Metal-Doped Nickel–Cobalt Layered Double Hydroxide Catalysts for an Efficient Oxygen Evolution Reaction
by Zhihan Li, Wenjing Yi, Qingqing Pang, Meng Zhang and Zhongyi Liu
Materials 2025, 18(4), 877; https://doi.org/10.3390/ma18040877 - 17 Feb 2025
Viewed by 1333
Abstract
Hydrogen plays a vital role in the global shift toward cleaner energy solutions, with water electrolysis standing out as one of the most promising techniques for generating hydrogen. Despite its potential, the oxygen evolution reaction (OER) involved in this process faces significant challenges, [...] Read more.
Hydrogen plays a vital role in the global shift toward cleaner energy solutions, with water electrolysis standing out as one of the most promising techniques for generating hydrogen. Despite its potential, the oxygen evolution reaction (OER) involved in this process faces significant challenges, including high overpotentials and slow reaction rates, which underscore the need for advanced electrocatalytic materials to enhance efficiency. Noble metal catalysts are effective but expensive, so transition-metal-based electrocatalysts like nickel–cobalt layered double hydroxides (NiCo LDHs) have become promising alternatives. In this research, a series of NiCo LDH catalysts doped with Fe, Mn, Cu, and Zn were effectively produced using a one-step hydrothermal technique. Among the catalysts, the Fe-doped NiCo LDH exhibited OER activity, achieving a lower overpotential (289 mV) at a current density of 50 mA/cm2, which was far better than the 450 mV of the undoped NiCo LDH. The Mn-, Cu-, and Zn-NiCo LDHs also exhibited lower overpotentials of 414 mV, 403 mV, and 357 mV, respectively, at this current density. The Fe-doped NiCo LDH had a 3D layered nanoflower structure, increasing the surface area for reactant adsorption. The electrochemically active surface area (ECSA), as indicated by the double-layer capacitance (Cdl), was larger in the doped samples. The Cdl value of the Fe-doped NiCo LDH was 3.72 mF/cm2, significantly surpassing the 0.82 mF/cm2 of the undoped NiCo LDH. These changes improved charge transfer and optimized reaction kinetics, enhancing the overall OER performance. This study offers significant contributions to the development of efficient electrocatalysts for the OER, advancing the understanding of key design principles for enhanced catalytic performance. Full article
(This article belongs to the Special Issue Research on Electrocatalytic Materials for Hydrogen Evolution and Oxygen Evolution)
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11 pages, 1999 KiB  
Article
Giant Seebeck Effect in a PEDOT Material Coated on a Felt Fiber
by Hideki Arimatsu, Yuki Osada, Ryo Takagi and Takuya Fujima
Materials 2025, 18(4), 838; https://doi.org/10.3390/ma18040838 - 14 Feb 2025
Viewed by 638
Abstract
Poly(3,4-ethylenedioxythiophene) (PEDOT) has been extensively investigated not only as a conductive polymer but also as a promising thermoelectric material. Numerous efforts have been undertaken to enhance the thermoelectric performance, particularly because improving the Seebeck coefficient is crucial for practical applications. In this study, [...] Read more.
Poly(3,4-ethylenedioxythiophene) (PEDOT) has been extensively investigated not only as a conductive polymer but also as a promising thermoelectric material. Numerous efforts have been undertaken to enhance the thermoelectric performance, particularly because improving the Seebeck coefficient is crucial for practical applications. In this study, we explored the thermoelectric property modification of PEDOT using a low-molecular carrier dopant and a fibrous substrate. PEDOT was coated on a felt texture with p-toluenesulfonic acid (PTSA) as the carrier dopant. The thermoelectric properties, including the Seebeck coefficient and electric conductivity, were measured. Raman spectroscopy was used to characterize the molecular strain of the PEDOT. The PEDOT sample coated on a felt texture with PTSA exhibited a wide range of Seebeck coefficients (−2100 to 3100 μV K−1). An estimation suggested the power factor reached 2400 µW m−1 K−2 for the p-type and 1100 µW m−1 K−2 for the n-type at the maxima. Raman spectroscopy showed a strong correlation between the strain in the Cβ-Cβ bond of the PEDOT molecule and its Seebeck coefficient. Full article
(This article belongs to the Special Issue Advanced Thin Film Materials for Energy Conversion and Storage Applications)
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14 pages, 7452 KiB  
Article
Light-Intensity-Dependent Control of Collagen Hydrogel Properties via Riboflavin Phosphate-Mediated Photocrosslinking
by Seungyeop Yoo, Won-Gun Koh and Hyun Jong Lee
Materials 2025, 18(4), 828; https://doi.org/10.3390/ma18040828 - 14 Feb 2025
Cited by 1 | Viewed by 927
Abstract
While photocrosslinked collagen hydrogels show promise in tissue engineering, conventional approaches for property control often require complex chemical modifications or concentration changes that alter their biochemical composition. Here, we present the first systematic investigation of light-intensity-dependent control in riboflavin phosphate (RFP)-mediated photocrosslinking as [...] Read more.
While photocrosslinked collagen hydrogels show promise in tissue engineering, conventional approaches for property control often require complex chemical modifications or concentration changes that alter their biochemical composition. Here, we present the first systematic investigation of light-intensity-dependent control in riboflavin phosphate (RFP)-mediated photocrosslinking as a novel, single-parameter approach to modulate hydrogel properties while preserving native biochemical environments. We systematically investigated the effects of varying light intensities (100 K, 50 K, and 10 K lux) during hydrogel fabrication through comprehensive structural, mechanical, and biological characterization. Scanning electron microscopy revealed unprecedented control over network architecture, where higher light intensities produced more uniform and compact networks, while swelling ratio analysis showed significant differences between 100 K lux (246 ± 2-fold) and 10 K lux (265 ± 4-fold) conditions. Most significantly, we discovered that intermediate intensity (50 K lux) uniquely optimized mechanical performance in physiological conditions, achieving storage modulus of about 220 Pa after 24 h swelling, compared to about 160 and 109 Pa for 100 K and 10 K lux conditions, respectively. Remarkably, cellular studies using NIH/3T3 fibroblasts demonstrated that lower light intensity (10 K lux) enhanced cell proliferation by 2.8-fold compared to 100 K lux conditions after 7 days of culture, with superior cell network formation in both 2D and 3D environments. This groundbreaking approach establishes light intensity as a powerful single parameter for precise control of both mechanical and biological properties, offering a transformative tool for tailoring collagen-based biomaterials in tissue engineering applications. Full article
(This article belongs to the Special Issue Advances in Bio-Polymer and Polymer Composites)
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23 pages, 10651 KiB  
Article
Dynamic Behavior of Submerged Cylindrical Shells Under Combined Underwater Explosion, Bubble Pulsation, and Hydrostatic Pressure
by Ruyi Fan, Gaojian Lin, Hang Zhang, Longfei Zhang and Weifu Sun
Materials 2025, 18(4), 818; https://doi.org/10.3390/ma18040818 - 13 Feb 2025
Cited by 1 | Viewed by 874
Abstract
Understanding the dynamic response of cylindrical shells subjected to underwater explosion is crucial for designing safe underwater vehicles, especially in deep-water environments where the shell structures are prestressed by hydrostatic pressure. The complex combination of external loading crossing different temporal scales—from underwater explosive [...] Read more.
Understanding the dynamic response of cylindrical shells subjected to underwater explosion is crucial for designing safe underwater vehicles, especially in deep-water environments where the shell structures are prestressed by hydrostatic pressure. The complex combination of external loading crossing different temporal scales—from underwater explosive shock waves to bubble pulsation and hydrostatic pressure—results in a synergic damaging effect on the target structures. In this work, the dynamic responses and buckling failure mechanisms of deeply immersed (≥1300 m) cylindrical shells subjected to underwater explosion were investigated through a numerical approach using the finite element method. A convenient and reliable routine for imposing hydrostatic pressure in the Coupled Eulerian–Lagrangian model was developed and validated. Three-dimensional models, composed of spherical charges and shell targets under deep-water conditions, were established to reveal the influences of key factors, including explosion depth and explosion distance, on the failure modes. The results show that the numerical models presented in this work are capable of simulating the complex synergic effect of hydrostatic pressure, the bubble pulsation process, and shock waves on the failure mechanisms of deeply immersed cylindrical shells. This work could provide valuable guidance for the design of safer deep-water marine structures. Full article
(This article belongs to the Special Issue Theoretical and Computational Modeling of Material Surfaces and Interfaces)
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15 pages, 8628 KiB  
Article
Improving Biodegradable Mg-Zn(-Ca) Alloys by Surface Treatment via Plasma Electrolytic Oxidation
by Jakub Vertaľ, Daniel Kajánek, Jiří Kubásek and Peter Minárik
Materials 2025, 18(4), 747; https://doi.org/10.3390/ma18040747 - 8 Feb 2025
Cited by 2 | Viewed by 718
Abstract
This study investigated the influence of plasma electrolytic oxidation (PEO) preparation time on the degradation resistance of Mg-1Zn (Z1) and Mg-1Zn-0.4Ca (ZX10) alloys, with comparisons to pure Mg and commercial Mg-4Y-3RE-0.4Zr (WE43). PEO layers were formed with varying preparation times (5, 10, and [...] Read more.
This study investigated the influence of plasma electrolytic oxidation (PEO) preparation time on the degradation resistance of Mg-1Zn (Z1) and Mg-1Zn-0.4Ca (ZX10) alloys, with comparisons to pure Mg and commercial Mg-4Y-3RE-0.4Zr (WE43). PEO layers were formed with varying preparation times (5, 10, and 15 min) and analyzed for microstructure, morphology, and corrosion resistance. The results indicated that PEO layers with a 10 min preparation time had the most homogeneous structure and optimal corrosion resistance. Prolonged PEO preparation times increased pore density, crack formation, and layer thickness while also promoting layer degradation during extended immersion in 0.9% NaCl corrosive media. The dissolution of phosphates from PEO layers contributes to the formation of a protective corrosion layer, enhancing long-term resistance. These findings demonstrate that low-alloyed, biocompatible Mg-Zn(-Ca) alloys can achieve corrosion resistance comparable to high-performance WE43 alloys through appropriate surface treatment. Full article
(This article belongs to the Special Issue Corrosion Behavior and Mechanical Properties of Metallic Materials)
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15 pages, 8890 KiB  
Article
Application of Magnetic-Assisted Polishing Using Metal-Bonded Grinding Wheels for Machining Silicon Nitride Ball Bearings
by Su-Yeon Han, Seung-Min Lee, Ha-Neul Kim, Jae-Woong Ko and Tae-Soo Kwak
Materials 2025, 18(3), 677; https://doi.org/10.3390/ma18030677 - 3 Feb 2025
Viewed by 906
Abstract
Silicon nitride (Si3N4) is used for high-speed rotating bearings in machine tools, aircraft, and turbo pumps due to its excellent material properties such as high-temperature strength, hardness, and fracture toughness. Grinding with fixed abrasives enables high shape accuracy and [...] Read more.
Silicon nitride (Si3N4) is used for high-speed rotating bearings in machine tools, aircraft, and turbo pumps due to its excellent material properties such as high-temperature strength, hardness, and fracture toughness. Grinding with fixed abrasives enables high shape accuracy and high efficiency in machining brittle materials. However, it is difficult to completely remove surface damage, which limits its use in products requiring a nano surface. These defects also result in reduced reliability and shortened lifespan. Magnetic-assisted polishing (MAP) is a technology that can achieve a fine surface by using a mixture of iron powder and abrasives, but it requires a lot of time due to the low material removal rate (MRR). Therefore, this study developed a hybrid processing technology using a metal-bonded grinding wheel and a slurry with hard abrasives for the high precision of silicon nitride ceramic ball bearings. Experiments were conducted in order to compare and analyze the surface roughness and material removal rate. Through MAP, using a grinding wheel with low grit (#325), high-efficiency machining performance was confirmed with a maximum material removal rate of 1.193 mg/min. In MAP, using a grinding wheel with high grit (#2000), a nano-level surface roughness of 6.5 nm Ra was achieved. Full article
(This article belongs to the Special Issue Functionalized Ceramics and Their Composites: Preparation, Properties and Applications)
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14 pages, 4269 KiB  
Article
Insights into HKUST-1 Metal-Organic Framework’s Morphology and Physicochemical Properties Induced by Changing the Copper(II) Salt Precursors
by Joanna Klęba, Kun Zheng, Dorota Duraczyńska, Mateusz Marzec, Monika Fedyna and Jakub Mokrzycki
Materials 2025, 18(3), 676; https://doi.org/10.3390/ma18030676 - 3 Feb 2025
Viewed by 2269
Abstract
The HKUST-1 metal-organic framework was synthesized using four different copper(II) salt precursors, namely copper nitrate, copper sulphate, copper acetate, and copper chloride, via the solvothermal method with no mixing. Syntheses were conducted without using the N,N-dimethylformamide to allow for a greener synthesis of [...] Read more.
The HKUST-1 metal-organic framework was synthesized using four different copper(II) salt precursors, namely copper nitrate, copper sulphate, copper acetate, and copper chloride, via the solvothermal method with no mixing. Syntheses were conducted without using the N,N-dimethylformamide to allow for a greener synthesis of MOFs. The selected physicochemical properties of the obtained metal-organic frameworks were determined. The yield of the obtained products changed in the order acetate>nitrate>sulfate, while no product was obtained in the synthesis with copper(II) chloride. The obtained materials were characterized by means of XRD, nitrogen adsorption–desorption at −196 °C, FTIR, XPS, TGA, SEM, and DLS. The morphology of crystallites and their physicochemical properties were significantly affected when different copper(II) salt precursors were used. The comparison of the obtained results with already published works allows for the correlation of the synthesis parameters like synthesis temperature, time, mixing, and copper(II) salt precursor used on selected properties of the final product. Full article
(This article belongs to the Special Issue Advanced Nanoporous and Mesoporous Materials)
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17 pages, 1743 KiB  
Article
Fabrication and Characterization of Electrospun DegraPol® Tubes Releasing TIMP-1 Protein to Modulate Tendon Healing
by Julia Rieber, Roger Khalid Niederhauser, Pietro Giovanoli and Johanna Buschmann
Materials 2025, 18(3), 665; https://doi.org/10.3390/ma18030665 - 3 Feb 2025
Cited by 3 | Viewed by 1001
Abstract
Background: Tendon rupture repair can result from fibrotic scar formation through imbalanced ECM deposition during remodeling. The tissue inhibitors of matrix metalloprotease (TIMPs) not only decrease ECM degradation, regulated by matrix metalloproteases (MMPs), but also restrict TGF-β1 activation and thus diminish fibrosis. Methods: [...] Read more.
Background: Tendon rupture repair can result from fibrotic scar formation through imbalanced ECM deposition during remodeling. The tissue inhibitors of matrix metalloprotease (TIMPs) not only decrease ECM degradation, regulated by matrix metalloproteases (MMPs), but also restrict TGF-β1 activation and thus diminish fibrosis. Methods: Rabbit tenocytes (rbTenocytes) and rabbit adipose-derived stem cells (rbASCs) were cultivated under different TIMP-1 concentrations. Proliferation and gene expression were assessed. TIMP-1 was incorporated into emulsion electrospun DegraPol® (DP) tubes that were characterized by SEM for fiber thickness, pore size, and wall thickness. Static and dynamic water contact angles, FTIR spectra, and TIMP-1 release kinetics were determined. Results: While the proliferation of rbTenocytes and rbACS was not affected by TIMP-1 supplementation in vitro, the gene expression of Col1A1 was increased in rbTenocytes, the gene expression of ki67 was increased in both cell types, the gene expression of tenomodulin was increased in both cell types at 100 ng/mL TIMP-1, and alkaline phosphatase expression ALP rose significantly in rbASCs. Electrospun TIMP-1/DP fibers had a ~5 μm diameter, a ~10 μm pore size, and a mesh thickness of ~200 μm. TIMP-1/DP meshes were more hydrophilic than pure DP meshes. TIMP-1 was released from the meshes with a sustained release of up to 7 days. Conclusions: TIMP-1/DP tubes may be used to modulate the fibrotic tissue reaction when applied around conventionally sutured tendon ruptures. Full article
(This article belongs to the Special Issue Physico-Chemical Modification of Materials for Biomedical Application)
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19 pages, 9311 KiB  
Article
B-H Curve Estimation and Air Gap Optimization for High-Performance Split Core
by Minjoong Kim, Myungseo Lee, Sijeong Lee, Jaeyun Lee and Jihwan Song
Materials 2025, 18(3), 644; https://doi.org/10.3390/ma18030644 - 31 Jan 2025
Viewed by 1201
Abstract
The current transformer (CT)-based energy harvesting method has gained considerable attention for low-power devices. Accurate estimation of the B-H curve is essential to develop a high-performance CT, as it closely relates to the electromagnetic behavior of CT material. However, the existing estimation methods [...] Read more.
The current transformer (CT)-based energy harvesting method has gained considerable attention for low-power devices. Accurate estimation of the B-H curve is essential to develop a high-performance CT, as it closely relates to the electromagnetic behavior of CT material. However, the existing estimation methods for the B-H curve face several drawbacks, which include process complexity and a high cost. This study presented an intuitive method to estimate the B-H curve based on the experimentally obtained resistance-voltage data. The performance of the CT core is obtained based on the estimated B-H curve, which exhibited an error of only 2.6% when compared to the experimental results for the most accurate case. Additionally, we analyzed split-core performance deterioration caused by the presence of an air gap. The air gap formation of the split core was closely related to the surface roughness, which significantly influenced core performance. The air gap range that minimizes the reduction in performance is predicted and validated through simulations and experiments. This research highlights a straightforward approach to obtaining the B-H curve of magnetic CT core material. We believe that this study provides the design guidelines needed to develop a high-performance CT core, including considerations for core geometry and the recommended air gap range. Full article
(This article belongs to the Special Issue Functional Soft Magnetic Materials and Electromagnetic Shielding Technology)
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17 pages, 3137 KiB  
Article
Efficient Photoelectrochemical Reduction of CO2 in Seawater with Cheap and Abundant Cu2O/Al2O3/TiO2 Electrode
by Aleksandra Parzuch, Katarzyna Kuder, Kostiantyn Nikiforow, Piotr Wróbel, Grzegorz Kaproń, Krzysztof Bieńkowski and Renata Solarska
Materials 2025, 18(3), 620; https://doi.org/10.3390/ma18030620 - 29 Jan 2025
Cited by 1 | Viewed by 969
Abstract
The photoelectrochemical (PEC) reduction of carbon dioxide to environmentally friendly fuels is a promising strategy to address the challenge of clean energy demand. Semiconductor photocathodes such as Cu2O enable the reduction of carbon dioxide, but their main drawback is their instability [...] Read more.
The photoelectrochemical (PEC) reduction of carbon dioxide to environmentally friendly fuels is a promising strategy to address the challenge of clean energy demand. Semiconductor photocathodes such as Cu2O enable the reduction of carbon dioxide, but their main drawback is their instability and susceptibility to photocorrosion. In this work, Al2O3 and TiO2 were utilized to enhance stability, photoelectrochemical activity, and charge transport facilitation, resulting in a 2.8-fold increase in generated photocurrent density (1.4 mA/cm2 at −0.2 V vs. RHE). The experiments were conducted in a 0.5 M NaCl solution, simulating seawater conditions, to evaluate the performance and stability of the system in an environment closer to real-world applications Full article
(This article belongs to the Special Issue Advances in Multicomponent Catalytic Materials)
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19 pages, 12564 KiB  
Article
Compressive Properties of Composite Sandwich Structure with Fractal Tree-Inspired Lattice Core
by Jian Han, Xin Ma, Rui Yang and Shiyong Sun
Materials 2025, 18(3), 606; https://doi.org/10.3390/ma18030606 - 29 Jan 2025
Viewed by 1069
Abstract
A novel sandwich structure of a fractal tree-like lattice (SSFL) is proposed. The geometry characteristics were constructed based on the fractal tree-like patterns found in many biological structures, such as giant water lilies and dragon blood trees. The compressive performance of the proposed [...] Read more.
A novel sandwich structure of a fractal tree-like lattice (SSFL) is proposed. The geometry characteristics were constructed based on the fractal tree-like patterns found in many biological structures, such as giant water lilies and dragon blood trees. The compressive performance of the proposed structures with different fractal orders was experimentally and numerically investigated. The experimental samples were made by 3D printing technology. Axial compression tests were conducted to study the compressive performance and failure mode of the SSFLs. The results indicated that the new structure was good at multiple bearing and energy absorption. The finite element method (FEM) was performed to investigate the influence of geometry parameters on the compression behaviors of the SSFLs. The findings of this study provide an effective guide for using the fractal method to design lattice structures with a high bearing capacity. Full article
(This article belongs to the Special Issue Advances in Porous Lightweight Materials and Lattice Structures)
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19 pages, 4921 KiB  
Article
Stiffness Compensation in Variable Displacement Mechanisms of Swash Plate Axial Piston Pumps Utilizing Piezoelectric Actuators
by Guangcheng Zhang, Mengxiang Ma and Yueh-Jaw Lin
Materials 2025, 18(3), 520; https://doi.org/10.3390/ma18030520 - 23 Jan 2025
Viewed by 874
Abstract
Swash plate axial piston pumps play an important role in hydraulic systems due to their superior performance and compact design. As the controlled object of the valve-controlled hydraulic cylinder, the swash plate is affected by the complex fluid dynamics effect and the mechanical [...] Read more.
Swash plate axial piston pumps play an important role in hydraulic systems due to their superior performance and compact design. As the controlled object of the valve-controlled hydraulic cylinder, the swash plate is affected by the complex fluid dynamics effect and the mechanical structure, which is prone to vibration, during the working process, thereby adversely affecting the dynamic performance of the system. In this paper, an electronically controlled ball screw type variable displacement mechanism with stiffness compensation is proposed. By introducing piezoelectric ceramic materials into the nut assembly, dynamic stiffness compensation of the system is achieved, which effectively changes the vibration characteristics of the swash plate and thus significantly improves the working stability of the system. Based on this, the stiffness model of a double nut ball screw is established to obtain the relationship between piezoelectric ceramics and the double nut. An asymmetric Bouc–Wen piezoelectric actuator model with nonlinear hysteresis characteristics is also established, and a particle swarm algorithm with improved inertia weights is utilized to identify the parameters of the asymmetric Bouc–Wen model. Finally, a piezoelectric actuator model based on the feedforward inverse model and a PID composite control algorithm is applied to the variable displacement mechanism system for stiffness compensation. Full article
(This article belongs to the Special Issue Advances in Smart Materials and Applications)
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26 pages, 7707 KiB  
Review
Textured Lead-Free Piezoelectric Ceramics: A Review of Template Effects
by Temesgen Tadeyos Zate, Cenk Abdurrahmanoglu, Vincenzo Esposito and Astri Bjørnetun Haugen
Materials 2025, 18(3), 477; https://doi.org/10.3390/ma18030477 - 21 Jan 2025
Cited by 3 | Viewed by 1616
Abstract
Crystallographic texture engineering through templated grain growth (TGG) has gained prominence as a highly effective strategy for optimizing the electromechanical performance of lead-free piezoelectric ceramics, offering a pathway toward sustainable alternatives to lead-based systems like lead zirconate titanate (PZT). By achieving high degrees [...] Read more.
Crystallographic texture engineering through templated grain growth (TGG) has gained prominence as a highly effective strategy for optimizing the electromechanical performance of lead-free piezoelectric ceramics, offering a pathway toward sustainable alternatives to lead-based systems like lead zirconate titanate (PZT). By achieving high degrees of texture, with Lotgering factors (LFs) often exceeding 90%, these systems have demonstrated piezoelectric properties that rival or even surpass their lead-based counterparts. Despite these advancements, the field lacks a comprehensive understanding of how specific template parameters influence the texture quality and functional properties across different material systems. This review provides an in-depth analysis of the influence of the template morphology, composition, and crystallographic orientation on the texturing of key lead-free systems, including BaTiO3 (BT), (K0.5Na0.5)NbO3 (KNN), and Bi0.5Na0.5TiO3 (BNT). Furthermore, it explores how the template selection affects the induced crystallographic direction, and how this impacts the material’s phase structure and domain configurations, ultimately influencing the piezoelectric and dielectric properties. By consolidating the existing knowledge and identifying current challenges, this work highlights key strategies for optimizing the texture and electromechanical performance in lead-free ceramics, providing essential insights for future research aimed at advancing high-performance, environmentally friendly piezoelectric materials for applications such as sensors, actuators, and energy-harvesting devices. Full article
(This article belongs to the Special Issue Sustainable Dielectric, Piezoelectric and Ferroelectric Materials: Synthesis, Characterization and Modelling)
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23 pages, 24751 KiB  
Article
From Powders to Performance—A Comprehensive Study of Two Advanced Cutting Tool Materials Sintered with Pressure Assisted Methods
by Kinga Momot, Piotr Klimczyk, Beata Leszczyńska-Madej, Marcin Podsiadło, Yuliia Rumiantseva and Agnieszka Gubernat
Materials 2025, 18(2), 461; https://doi.org/10.3390/ma18020461 - 20 Jan 2025
Viewed by 1035
Abstract
This paper presents a comprehensive study of two tool materials designed for the machining of Inconel 718 superalloy, produced through two distinct sintering techniques: High Pressure–High Temperature (HPHT) sintering and Spark Plasma Sintering (SPS). The first composite (marked as BNT), composed of 65 [...] Read more.
This paper presents a comprehensive study of two tool materials designed for the machining of Inconel 718 superalloy, produced through two distinct sintering techniques: High Pressure–High Temperature (HPHT) sintering and Spark Plasma Sintering (SPS). The first composite (marked as BNT), composed of 65 vol% cubic boron nitride (cBN), was sintered from the cBN–TiN–Ti3SiC2 system using the HPHT technique at a pressure of 7.7 GPa. The second composite (marked as AZW) was fabricated from the Al2O3–ZrO2–WC system using SPS at a pressure of 63 MPa. The final phase composition of BNT material differed significantly from the initial composition due to reactions occurred during sintering. In contrast, the phase composition of the AZW ceramic composite before and after sintering was similar. The materials exhibited high quality, as evidenced by a Young’s modulus of 580 GPa for BNT and 470 GPa for AZW, along with hardness of 26 GPa for BNT and 21 GPa for AZW. Both composites were used to prepare cutting inserts that were evaluated for their performance in machining Inconel 718 alloy. While both inserts showed durability comparable to their respective reference commercial inserts, they differed in performance and price relative to one another. Full article
(This article belongs to the Special Issue Advances in Multifunctional Materials Obtained at High Temperature and Pressure Conditions)
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17 pages, 3373 KiB  
Review
Materials with Negative Permittivity or Negative Permeability—Review, Electrodynamic Modelling, and Applications
by Jerzy Krupka
Materials 2025, 18(2), 423; https://doi.org/10.3390/ma18020423 - 17 Jan 2025
Cited by 1 | Viewed by 1755
Abstract
A review of natural materials that exhibit negative permittivity or permeability, including gaseous plasma, metals, superconductors, and ferromagnetic materials, is presented. It is shown that samples made of such materials can store large amount of the electric (magnetic) energy and create plasmonic resonators [...] Read more.
A review of natural materials that exhibit negative permittivity or permeability, including gaseous plasma, metals, superconductors, and ferromagnetic materials, is presented. It is shown that samples made of such materials can store large amount of the electric (magnetic) energy and create plasmonic resonators for certain values of permittivity, permeability, and dimensions. The electric and the magnetic plasmon resonances in spherical samples made of such materials are analyzed using rigorous electrodynamic methods, and the results of the analysis are compared to experimental data and to results obtained with other methods. The results of free oscillation and Mie scattering theories are compared. Similarities and differences between permittivity and permeability tensors for magnetized plasma and magnetized ferromagnetic materials are underlined. Several physical phenomena are explained on the grounds of rigorous electrodynamic analysis and experiments. These phenomena include unequal electric and magnetic energies stored in plasmonic resonators, the small influence of dielectric losses on the Q-factors of magnetic plasmon resonances, the role of radiation and dissipation losses on the properties of plasmonic resonators, and the theoretical possibility of the existence of lightning plasma balls. Full article
(This article belongs to the Section Materials Physics)
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24 pages, 5889 KiB  
Article
Effect of Plasma Treatment on Coating Adhesion and Tensile Strength in Uncoated and Coated Rubber Under Aging
by Miguel Angel Martínez, Juana Abenojar and Daniel García-Pozuelo
Materials 2025, 18(2), 427; https://doi.org/10.3390/ma18020427 - 17 Jan 2025
Cited by 1 | Viewed by 918
Abstract
The degradation of rubber materials under environmental and mechanical stress presents a significant challenge, particularly due to UV (ultraviolet light) exposure, which severely impacts the material’s physical properties. This study aims to enhance the UV stability and longevity of rubber by evaluating the [...] Read more.
The degradation of rubber materials under environmental and mechanical stress presents a significant challenge, particularly due to UV (ultraviolet light) exposure, which severely impacts the material’s physical properties. This study aims to enhance the UV stability and longevity of rubber by evaluating the performance of modified polyurethane and silicone coatings as protective stabilizers. Natural rubber—styrene–butadiene rubber (NR-SBR), known for its exceptional mechanical properties, was selected as the base material. To ensure strong adhesion, cold atmospheric plasma treatment was applied, increasing the surface energy by 250%, primarily through an enhancement of the polar component. After treatment, supplier-recommended coatings were applied and tested for adhesion using the pull-out method. Aging tests under UV exposure, water immersion, and high temperatures were conducted to assess durability, with tensile tests used to monitor changes over time. Coatings exhibiting cracking after UV exposure were excluded from further analysis. A silicone coating demonstrating superior moisture resistance and durability under extreme conditions was identified as a promising candidate for future UV stabilization applications. These findings provide a foundation for developing advanced coatings to significantly extend the service life of rubber materials in demanding environments. Full article
(This article belongs to the Special Issue Advanced Rubber Composites (3rd Edition）)
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24 pages, 16306 KiB  
Article
Digital Image Correlation and Numerical Analysis of Mechanical Behavior in Photopolymer Resin Lattice Structures
by Arkadiusz Popławski, Paweł Bogusz and Maciej Grudnik
Materials 2025, 18(2), 384; https://doi.org/10.3390/ma18020384 - 16 Jan 2025
Cited by 2 | Viewed by 1009
Abstract
Cellular structures are increasingly utilized in modern engineering due to their exceptional mechanical and physical properties. In this study, the deformation and failure mechanisms of two energy-efficient lattice structures—hexagonal honeycomb and re-entrant honeycomb—were investigated. These structures were manufactured using additive stereolithography with light-curable [...] Read more.
Cellular structures are increasingly utilized in modern engineering due to their exceptional mechanical and physical properties. In this study, the deformation and failure mechanisms of two energy-efficient lattice structures—hexagonal honeycomb and re-entrant honeycomb—were investigated. These structures were manufactured using additive stereolithography with light-curable Durable Resin V2. The experimental testing of the topologies under two perpendicular loading directions employed the 3D Digital Image Correlation (DIC) system to capture strain fields and deformation patterns, providing insights into structural behavior and failure mechanisms. The unit cells of the topologies were scaled up to enable precise optical measurements while preserving their structural interaction characteristics. Numerical simulations, conducted using the SAMP-1 material model in LS-DYNA and calibrated with tensile and compression test data, accurately replicated the behavior of the studied topologies and demonstrated good agreement with experimental results. The hexagonal structure, loaded along axis 2, showed the best fit, with deviations within 5%, while the re-entrant honeycomb structure exhibited weaker yet reasonable agreement. By integrating experimental and numerical approaches, the research validates the SAMP-1 model’s predictive capabilities for lattice structures and provides a framework for analyzing energy-absorbing lattice topologies. Full article
(This article belongs to the Section Polymeric Materials)
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16 pages, 5275 KiB  
Article
Optimization of In-Situ Growth of Superconducting Al/InAs Hybrid Systems on GaAs for the Development of Quantum Electronic Circuits
by Magdhi Kirti, Máté Sütő, Endre Tóvári, Péter Makk, Tamás Prok, Szabolcs Csonka, Pritam Banerjee, Piu Rajak, Regina Ciancio, Jasper R. Plaisier, Pietro Parisse and Giorgio Biasiol
Materials 2025, 18(2), 385; https://doi.org/10.3390/ma18020385 - 16 Jan 2025
Viewed by 1836
Abstract
Hybrid systems consisting of highly transparent channels of low-dimensional semiconductors between superconducting elements allow the formation of quantum electronic circuits. Therefore, they are among the novel material platforms that could pave the way for scalable quantum computation. To this aim, InAs two-dimensional electron [...] Read more.
Hybrid systems consisting of highly transparent channels of low-dimensional semiconductors between superconducting elements allow the formation of quantum electronic circuits. Therefore, they are among the novel material platforms that could pave the way for scalable quantum computation. To this aim, InAs two-dimensional electron gases are among the ideal semiconductor systems due to their vanishing Schottky barrier; however, their exploitation is limited by the unavailability of commercial lattice-matched substrates. We show that in situ growth of superconducting aluminum on two-dimensional electron gases forming in metamorphic near-surface InAs quantum wells can be performed by molecular beam epitaxy on GaAs substrates with state-of-the-art quality. Adaptation of the metamorphic growth protocol has allowed us to reach low-temperature electron mobilities up to 1.3 × 105 cm2/Vs in Si-doped InAs/In0.81Ga0.19As two-dimensional electron gases placed 10 nm from the surface with charge density up to 1 × 1012/cm2. Shubnikov-de Haas oscillations on Hall bar structures show well-developed quantum Hall plateaus, including the Zeeman split features. X-ray diffraction and cross-sectional transmission electron microscopy experiments demonstrate the coexistence of (011) and (111) crystal domains in the Al layers. The resistivity of 10-nm-thick Al films as a function of temperature was comparable to the best Al layers on GaAs, and a superconducting proximity effect was observed in a Josephson junction. Full article
(This article belongs to the Special Issue Thin Films and Semiconductor Heterostructures: From Fundamental to Applications)
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25 pages, 26496 KiB  
Article
Antibacterial Properties of PMMA/ZnO(NanoAg) Coatings for Dental Implant Abutments
by Ana Maria Gianina Rehner (Costache), Dana-Ionela Tudorache, Alexandra Cătălina Bîrcă, Adrian Ionuț Nicoară, Adelina-Gabriela Niculescu, Alina Maria Holban, Ariana Hudiță, Florentina Cornelia Bîclesanu, Paul Cătălin Balaure, Anna Maria Pangică, Alexandru Mihai Grumezescu and George-Alexandru Croitoru
Materials 2025, 18(2), 382; https://doi.org/10.3390/ma18020382 - 15 Jan 2025
Viewed by 1735
Abstract
Infections continue to pose significant challenges in dentistry, necessitating the development of innovative solutions that can effectively address these issues. This study focuses on creating coatings made from polymethyl methacrylate (PMMA) enriched with zinc oxide–silver composite nanoparticles, layered to Ti6Al4V–titanium alloy substrates. The [...] Read more.
Infections continue to pose significant challenges in dentistry, necessitating the development of innovative solutions that can effectively address these issues. This study focuses on creating coatings made from polymethyl methacrylate (PMMA) enriched with zinc oxide–silver composite nanoparticles, layered to Ti6Al4V–titanium alloy substrates. The application of these materials aims to create a solution for the abutments utilized in complete dental implant systems, representing the area most susceptible to bacterial infections. The nanoparticles were synthesized using a hydrothermal method, optimized through specific temperature and pressure parameters to achieve effective morphologies and sizes that enhance antibacterial efficacy. The layers were applied to the titanium substrate using the spin coating technique, chosen for its advantages and compatibility with the materials involved. Comprehensive analyses were conducted on the antimicrobial powders, including X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Furthermore, the PMMA-based coatings incorporating antimicrobial nanoparticles were evaluated to ensure uniformity and homogeneity across the titanium alloy surface by IR mapping and SBF immersion–SEM analysis. The antimicrobial activity of the samples was demonstrated with impressive results against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, as assessed through biofilm modulation studies. The biocompatibility of the samples was validated through in vitro cell-based assays, which demonstrated excellent compatibility between PMMA-based coatings and human preosteoblasts, confirming their potential suitability for future use in dental implants. Full article
(This article belongs to the Special Issue Advances in New Alloys, Polymers and Composites for Biomedical Applications)
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18 pages, 4252 KiB  
Article
Bilayer TiO2/Mo-BiVO4 Photoelectrocatalysts for Ibuprofen Degradation
by Martha Pylarinou, Elias Sakellis, Spiros Gardelis, Vassilis Psycharis, Marios G. Kostakis, Nikolaos S. Thomaidis and Vlassis Likodimos
Materials 2025, 18(2), 344; https://doi.org/10.3390/ma18020344 - 14 Jan 2025
Cited by 1 | Viewed by 1307
Abstract
Heterojunction formation between BiVO4 nanomaterials and benchmark semiconductor photocatalysts has been keenly pursued as a promising approach to improve charge transport and charge separation via interfacial electron transfer for the photoelectrocatalytic degradation of recalcitrant pharmaceutical pollutants. In this work, a heterostructured TiO [...] Read more.
Heterojunction formation between BiVO4 nanomaterials and benchmark semiconductor photocatalysts has been keenly pursued as a promising approach to improve charge transport and charge separation via interfacial electron transfer for the photoelectrocatalytic degradation of recalcitrant pharmaceutical pollutants. In this work, a heterostructured TiO2/Mo-BiVO4 bilayer photoanode was fabricated by the deposition of a mesoporous TiO2 overlayer using the benchmark P25 titania catalyst on top of Mo-doped BiVO4 inverse opal films as the supporting layer, which intrinsically absorbs visible light below 490 nm, while offering improved charge transport. A porous P25/Mo-BiVO4 bilayer structure was produced from the densification of the inverse opal underlayer after post-thermal annealing, which was evaluated on photocurrent generation in aqueous electrolyte and the photoelectrocatalytic degradation of the refractory anti-inflammatory drug ibuprofen under back-side illumination by visible and UV–Vis light. Significantly enhanced photoelectrochemical performance on both photocurrent density and pharmaceutical degradation was achieved for the bilayer structure with respect to the additive effect of the constituent layers, which was related to the improved light harvesting arising from the backscattering by the mesoporous TiO2 layer in combination with the favorable charge transfer at the TiO2/Mo-BiVO4 interface. Full article
(This article belongs to the Special Issue Feature Papers in Materials Physics (2nd Edition))
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21 pages, 8799 KiB  
Article
Four-Dimensional Printing of β-Tricalcium Phosphate-Modified Shape Memory Polymers for Bone Scaffolds in Osteochondral Regeneration
by Izabella Rajzer, Anna Kurowska, Jarosław Janusz, Maksymilian Maślanka, Adam Jabłoński, Piotr Szczygieł, Janusz Fabia, Roman Novotný, Wojciech Piekarczyk, Magdalena Ziąbka and Jana Frankova
Materials 2025, 18(2), 306; https://doi.org/10.3390/ma18020306 - 11 Jan 2025
Cited by 1 | Viewed by 1237
Abstract
The use of scaffolds for osteochondral tissue regeneration requires an appropriate selection of materials and manufacturing techniques that provide the basis for supporting both cartilage and bone tissue formation. As scaffolds are designed to replicate a part of the replaced tissue and ensure [...] Read more.
The use of scaffolds for osteochondral tissue regeneration requires an appropriate selection of materials and manufacturing techniques that provide the basis for supporting both cartilage and bone tissue formation. As scaffolds are designed to replicate a part of the replaced tissue and ensure cell growth and differentiation, implantable materials have to meet various biological requirements, e.g., biocompatibility, biodegradability, and mechanical properties. Osteoconductive materials such as tricalcium phosphate ceramics and some biodegradable polymers appear to be a perfect choice. The present work evaluates the structural, mechanical, thermal, and functional properties of a shape memory terpolymer modified with β-tricalcium phosphate (β-TCP). A new approach is using the developed materials for 4D printing, with a particular focus on its applicability in manufacturing medical implants. In this study, the manufacturing parameters of the scaffold components were developed. The scaffolds were examined via scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and mechanical testing. The cytotoxicity result was obtained with an MTT assay, and the alkaline phosphatase (ALP) activity was measured. The structural and microstructural investigations confirmed the integration of β-TCP into the filament matrix and scaffolds. Thermal stability was enhanced as β-TCP delayed depolymerization of the polymer matrix. The shape memory studies demonstrated effective recovery. The in vitro cell culture studies revealed the significantly increased cell viability and alkaline phosphatase (ALP) activity of the β-TCP-modified terpolymer after 3 weeks. The developed terpolymer can be tailored for applications in which partial shape recovery is acceptable, such as bone scaffolds. Full article
(This article belongs to the Section Biomaterials)
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19 pages, 2447 KiB  
Article
Evaluation of the Tribological Behavior of Materials Used for the Production of Orthodontic Devices in 3D DLP Printing Technology, Due to Oral Cavity Environmental Factors
by Andrzej Snarski-Adamski, Daniel Pieniak, Zbigniew Krzysiak, Marcel Firlej and František Brumerčík
Materials 2025, 18(2), 301; https://doi.org/10.3390/ma18020301 - 10 Jan 2025
Cited by 3 | Viewed by 1173
Abstract
This study evaluated the effect of oral cavity environmental factors on the friction and wear of materials used in 3D-printed orthodontic devices. Commercial materials GR-10 (Pro3Dure) and NextDent SG (NextDent) were examined, with samples produced using ASIGA UV MAX and Phrozen Shuffle Lite [...] Read more.
This study evaluated the effect of oral cavity environmental factors on the friction and wear of materials used in 3D-printed orthodontic devices. Commercial materials GR-10 (Pro3Dure) and NextDent SG (NextDent) were examined, with samples produced using ASIGA UV MAX and Phrozen Shuffle Lite 3D printers. Our tests included measurements of hardness, stiffness, elastic modulus, cyclic loading, scratch resistance, and tribological assessments in oscillatory motion. Surface analyses were conducted using scanning electron microscopy with an energy-dispersive spectroscopy analyzer. The results showed that NextDent SG exhibited higher hardness and modulus of elasticity, while GR-10 demonstrated better scratch resistance. Despite similar friction coefficients, significant variations in wear were observed under different environmental conditions, highlighting the importance of considering these factors in the performance of orthodontic materials. Full article
(This article belongs to the Section Polymeric Materials)
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38 pages, 18491 KiB  
Review
Review of the Microstructural Impact on Creep Mechanisms and Performance for Laser Powder Bed Fusion Inconel 718
by Guillian Bryndza, Jérôme Tchoufang Tchuindjang, Fan Chen, Anne Marie Habraken, Héctor Sepúlveda, Víctor Tuninetti, Anne Mertens and Laurent Duchêne
Materials 2025, 18(2), 276; https://doi.org/10.3390/ma18020276 - 9 Jan 2025
Cited by 3 | Viewed by 2091
Abstract
Inconel 718 (IN718) is a polycrystalline nickel-based superalloy and one of the most widely used materials in the aerospace industry owing to its excellent mechanical performances at high temperatures, including creep resistance. Interest in additively manufactured components in aerospace is greatly increasing due [...] Read more.
Inconel 718 (IN718) is a polycrystalline nickel-based superalloy and one of the most widely used materials in the aerospace industry owing to its excellent mechanical performances at high temperatures, including creep resistance. Interest in additively manufactured components in aerospace is greatly increasing due to their ability to reduce material consumption, to manufacture complex parts, and to produce out-of-equilibrium microstructures, which can be beneficial for mechanical behavior. IN718’s properties are, however, very sensitive to microstructural features, which strongly depend on the manufacturing process and subsequent heat treatments. Additive manufacturing and, more specifically, Laser Powder Bed Fusion (LPBF) induces very high thermal gradients and anisotropic features due to its inherently directional nature, which largely defines the microstructure of the alloy. Hence, defining appropriate manufacturing parameters and heat treatments is critical to obtain appropriate mechanical behavior. This review aims to present the main microstructural features of IN718 produced by LPBF, the creep mechanisms taking place, the optimal microstructure for creep strength, and the most efficient heat treatments to yield such an optimized microstructure. Full article
(This article belongs to the Special Issue Quality, Microstructure and Properties of Metal Alloys (Second Volume))
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16 pages, 1625 KiB  
Article
Long-Term Clinical Study on Sandblasted–Acid-Etched Surface Dental Implants: 12-Year Follow-Up
by Eugenio Velasco-Ortega, Jesús Pato-Mourelo, Borja López-López, Loreto Monsalve-Guil, Jesús Moreno-Muñoz, José López-López, Enrique Núñez-Márquez, Nuno Matos Garrido, José Luis Rondón-Romero, Álvaro Jiménez-Guerra and Iván Ortiz-García
Materials 2025, 18(1), 183; https://doi.org/10.3390/ma18010183 - 4 Jan 2025
Viewed by 1227
Abstract
Sandblasting and acid etching are common procedures used to treat implant surfaces, enhancing osseointegration and improving clinical success rates. This clinical study aimed to evaluate the long-term outcomes of sandblasted and acid-etched implants. A total of 303 implants were placed in 114 partially [...] Read more.
Sandblasting and acid etching are common procedures used to treat implant surfaces, enhancing osseointegration and improving clinical success rates. This clinical study aimed to evaluate the long-term outcomes of sandblasted and acid-etched implants. A total of 303 implants were placed in 114 partially and totally edentulous patients using a two-stage surgical technique and an early loading protocol (6–8 weeks). Clinical findings for implants and prosthetics were evaluated over a 12-year follow-up period. A total of 12 implants (3.9%) failed, with 3 failures occurring during the healing period before loading and 9 due to peri-implantitis. The cumulative survival rate for all implants was 96.1%. A total of 156 prostheses were placed on 300 implants, 87 single crowns, 45 partial fixed bridges, 9 full-arch fixed restorations, and 15 overdentures. The mean marginal bone loss was 1.18 mm. (SD. 0.64 mm.). Thirty-nine implants (13%) in twenty-four patients exhibited peri-implantitis. Technical complications, including prosthetic screw loosening or fracture, ceramic chipping, and acrylic fractures, were observed in 24 subjects (21.1%). Sandblasted and acid-etched surface implants placed in the maxilla and mandible reported favorable outcomes and stable tissue conditions with an early loading protocol. Full article
(This article belongs to the Special Issue Advances in Dental Implants: Materials, Procedures and Clinical Response)
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40 pages, 9273 KiB  
Review
Revisiting Intercalation Anode Materials for Potassium-Ion Batteries
by María José Piernas-Muñoz and Maider Zarrabeitia
Materials 2025, 18(1), 190; https://doi.org/10.3390/ma18010190 - 4 Jan 2025
Cited by 3 | Viewed by 2040
Abstract
Potassium-ion batteries (KIBs) have attracted significant attention in recent years as a result of the urgent necessity to develop sustainable, low-cost batteries based on non-critical raw materials that are competitive with market-available lithium-ion batteries. KIBs are excellent candidates, as they offer the possibility [...] Read more.
Potassium-ion batteries (KIBs) have attracted significant attention in recent years as a result of the urgent necessity to develop sustainable, low-cost batteries based on non-critical raw materials that are competitive with market-available lithium-ion batteries. KIBs are excellent candidates, as they offer the possibility of providing high power and energy densities due to their faster K+ diffusion and very close reduction potential compared with Li+/Li. However, research on KIBs is still in its infancy, and hence, more investigation is required both at the materials level and at the device level. In this work, we focus on recent strategies to enhance the electrochemical properties of intercalation anode materials, i.e., carbon-, titanium-, and vanadium-based compounds. Hitherto, the most promising anode materials are those carbon-based, such as graphite, soft, or hard carbon, each with its advantages and disadvantages. Although a wide variety of strategies have been reported with excellent results, there is still a need to improve the standardization of the best carbon properties, electrode formulation, and electrolyte composition, given the impossibility of a direct comparison. Therefore, additional effort should be made to understand what are the crucial carbon parameters to develop a reference electrode and electrolyte formulation to further boost their performance and move a step forward in the commercialization of KIBs. Full article
(This article belongs to the Special Issue Advanced Anode Materials for Alkali-Ion Batteries)
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15 pages, 3362 KiB  
Article
Mechanical and Energy Evolution Characteristics of Fractured Sandstone Materials: A True Triaxial Experimental Study
by Guowen Sun, Yu Lu, Gun Huang, Qinming Liang and Xinyu Huang
Materials 2025, 18(1), 175; https://doi.org/10.3390/ma18010175 - 3 Jan 2025
Cited by 1 | Viewed by 738
Abstract
To investigate the mechanical and energy evolution characteristics of fractured rock under true triaxial stresses, true triaxial strength compression experiments on fractured sandstone were conducted with varying crack lengths and widths. The results indicate that under true triaxial stresses, the peak stress of [...] Read more.
To investigate the mechanical and energy evolution characteristics of fractured rock under true triaxial stresses, true triaxial strength compression experiments on fractured sandstone were conducted with varying crack lengths and widths. The results indicate that under true triaxial stresses, the peak stress of the rock exhibits a gradual decline with an increase in crack length and width. Meanwhile, crack initiation stress and crack damage stress of fractured sandstone also demonstrate a declining trend overall, and the influence of crack length on the characteristic stress (crack initiation stress and crack damage stress) of sandstone is more pronounced than that of crack width. According to the energy analysis results, the total strain energy of fractured sandstone gradually decreases with an increase in crack length and width. The results offer a theoretical foundation for the strength assessment and stability management of fractured rock materials during deep coal mining operations. Full article
(This article belongs to the Special Issue Microstructure, Characterization and Mechanical Properties of Coal and Coal-Like Materials (2nd Edition))
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13 pages, 11047 KiB  
Article
Memory Effect of Double Oxides Compared to Simple Ion Exchange for Controlled Fluoride Ion Capture and Release
by Asma Alazreg, Vladisav Tadić, Adela Egelja, Andrija Savić, Aleksandra Šaponjić, Marija M. Vuksanović and Radmila Jančić Heinemann
Materials 2025, 18(1), 162; https://doi.org/10.3390/ma18010162 - 3 Jan 2025
Cited by 1 | Viewed by 921
Abstract
A layered double hydroxide (LDH) containing Mg and Al was synthesized from a nitrate solution using a coprecipitation method. The resulting material exhibited a homogeneous structure, which, upon calcination at 450 °C, was converted into a layered double oxide (LDO). When rehydrated in [...] Read more.
A layered double hydroxide (LDH) containing Mg and Al was synthesized from a nitrate solution using a coprecipitation method. The resulting material exhibited a homogeneous structure, which, upon calcination at 450 °C, was converted into a layered double oxide (LDO). When rehydrated in a fluoride-containing aqueous solution, the original hydroxide structure was successfully regenerated, demonstrating the LDH’s memory effect. During this transformation, fluoride anions from the solution were incorporated into the interlayer galleries to maintain electroneutrality, as confirmed by energy-dispersive X-ray spectroscopy (EDS) analysis. Separately, the process was tested in the presence of ethanol, which significantly enhanced the incorporation of fluoride ions into the interlayer spaces. The material’s potential for controlled fluoride release was evaluated by monitoring its release into demineralized water. For comparison, a simple ion-exchange process was carried out using the as-synthesized MgAl LDH. The memory effect mechanism displayed a notably higher fluoride incorporation capacity compared to the ion-exchange process. Among all the specimens, the sample reconstructed in the presence of ethanol exhibited the highest fluoride ion content. Fluoride release studies revealed a two-phase pattern: an initial rapid release within the first three hours, followed by a substantially slower release over time. Full article
(This article belongs to the Special Issue Graphene and Other 2D Layered Nanomaterials and Hybrid Structures: Synthesis, Properties and Applications (Volume II))
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