Materials Horizons最新文献

Lignin is the second most abundant renewable and sustainable biomass resource. Developing advanced manufacturing to process lignin/lignocellulose into functional materials could reduce the consumption of petroleum-based materials. 3D printing provides a promising strategy to realize complex and customized geometries of lignin materials. The heterogeneity and complexity of lignin hinder its processing via additive manufacturing, but the recent advancement in lignin modification and polymerization provides new opportunities. Here, we summarize the recent state-of-the-art 3D printing of lignin materials, including the selection and formulation of lignin materials based on different printing techniques, the chemical modification of lignin for enhanced printability, and the related application fields. Additionally, we highlight the significant role of the 3D printing of lignocellulose biomass materials, such as wood powder and agricultural wastes. It was concluded that the most challenging part is to enhance the printability of lignin materials through modification and pretreatment of lignin while keeping the whole process green and sustainable. Beyond 3D printing, we further discuss the development of smart lignin materials and their potential for 4D printing. Ultimately, we discuss the current challenges and potential opportunities for the additive manufacturing of lignin materials. We believe this review can raise awareness among researchers about the potential of lignin materials as whole materials for constructing blocks and can promote the development of 3D/4D printing of lignin towards sustainability.

Multifunctional devices based on van der Waals heterojunctions have drawn significant attention owing to their portable size, low power consumption and various application scenarios. However, high fabrication equipment requirements, complex device structures and limited operating conditions hinder their potential value. Herein, multifunctional UV photodetect-memristors based on Ga₂S₃/graphene/GaN van der Waals heterojunctions via area selective deposition have been proposed for the first time. The Ga₂S₃/graphene/GaN heterojunctions are firstly grown via area selective deposition (ASD) without a mask plate or lithography process. And the corresponding molecular dynamics (MD) and density functional theory (DFT) simulation further confirmed its feasibility and physical properties. Subsequently, multifunctional devices based on Ga₂S₃/graphene/GaN heterojunctions are fabricated accordingly, and exhibit ultrafast (<80 μs) response at 0 V and stable, highly sensitive (1150.4 A W^-1) memory features at 3 V. Here, the huge hole barriers formed on the two edges of graphene set the foundation of trapping and detecting light-induced carriers. Afterwards, handwriting numeral recognition tasks are carried out based on the performance extracted from the device and a simplified noise filtering and improved recognition accuracy system is proposed, confirming its application potential in the artificial intelligence area. This study proposes a practical way to grow large-size 2D materials selectively, shows the valuable application potential of p-g-n heterojunctions in various application fields, and expands an innovative path of device development in the post-Moorish era.

The complex synthetic approach and utilization of toxic chemicals restrain the commercialization of numerous existing superhydrophobic materials. This article focuses on the development of a halogen-free superhydrophobic material for self-cleaning applications. HMDS-modified MCM-41 is employed as the base material. Silanization within the silica-framework is strategically improved by introducing the concept of surface-acidity enhancement by suitable heteroatom (Al, Ti and Zr) incorporation. The role of heteroatoms in defining the surface acidity of MCM-41 is analyzed in terms of solubility limit, ionic radii and electronegativity of the heteroatoms. Additionally, this work exclusively discusses the solvent selection criteria for the synthesis of hydrophobic materials and their role in enhancing hydrophobicity, evaluated via UV-visible turbidity measurements. Based on extensive studies, silane modified 25% Al-MCM-41 dispersed in acetonitrile exhibits exceptional water repellence with a water contact angle of 172.4 ± 0.7°. Higher electropositivity and the trivalent bonding nature of Al facilitate efficient silane modification and reduced surface OH concentration, leading to improved material hydrophobicity. Remarkable self-cleaning capability combined with durability and resilience towards diverse harsh conditions strengthen the practical viability of the designed material. Life cycle assessment (LCA) suggested that the material exhibits a smaller environmental footprint in terms of 18 selected midpoint indicators compared to the state-of-the-art materials.

Polymer photo-oxidation aging is a significant issue in plastics engineering, leading to reduced performance, shorter lifespan, and additional pollution. Anti-aging agents, including antioxidants and ultraviolet (UV)-shielding agents, are used to ameliorate the above problems. However, multi-component agents involve complex synthesis, mixed processing, and environmental concerns. Therefore, developing robust, multi-functional, one-component anti-aging agents is crucial. This study proposed a new class of one-component poly(coumarin) anti-aging agents, synthesized through enzymatic polymerization of coumarin. These agents exhibited a broader UV absorption spectrum and higher antioxidative capacity than commercial UV-shielding agent UV326 and antioxidant AO1010. Calculating the O-H bond dissociation energy and reaction energy barrier with peroxy free radicals (ROO˙) showed that the material could effectively attenuate UV radiation and scavenge free radicals, improving anti-aging properties. Further studies indicated the potential of poly(coumarin) anti-aging agents for enhanced polymer photostability and improved food preservation packaging. Consequently, poly(coumarin) nanoparticles can act as versatile anti-aging compounds, potentially replacing conventional multi-component agents and providing a new foundation for one-component materials with multiple functions.

It is difficult to intuit how electronic structure features-such as band gap magnitude, location of band extrema, effective masses, etc.-arise from the underlying crystal chemistry of a material. Here we present a strategy to distill sparse and chemically-interpretable tight-binding models from density functional theory calculations, enabling us to interpret how multiple orbital interactions in a 3D crystal conspire to shape the overall band structure. Applying this process to silicon, we show that its indirect gap arises from a competition between first and second nearest-neighbor bonds-where second nearest-neighbor interactions pull the conduction band down from Γ to X in a cosine shape, but the first nearest-neighbor bonds push the band up near X, resulting in the characteristic dip of the silicon conduction band. By identifying the essential orbital interactions that shape the conduction band, we can further rationally tune bond strengths to morph the silicon band structure into the germanium band structure. Our computational approach serves as a general framework to extract the crystal chemistry origins of electronic structure features from density functional theory calculations, enabling a new paradigm of bonding-by-design.

Solar energy sources have garnered significant attention as a renewable energy option. Despite this, the practical power conversion efficiency (PCE) of widely used silicon-based solar cells remains low due to inefficient light utilization. In this study, carbon dots (APCDs) were prepared via a hydrothermal method using ammonium polyphosphate and m-phenylenediamine, then incorporated into a silicone-acrylic emulsion (CAS) to create a luminescent down-shifting (LDS) layer for solar cells. The CAS/APCDs films can be molded at room temperature and exhibit outstanding optical and adhesive properties. Application of CAS/APCDs films on solar cell surfaces effectively enhances photovoltaic performance, increasing current density (J_SC) by 3.5% and overall PCE by 5.7%. Additionally, APCDs enhance flame retardancy in CAS films, increasing the limiting oxygen index from 29.3% to 32.0%, while reducing peak heat release and peak CO release by 20.2% and 38.9%, respectively. Moreover, APCDs absorb UV light and convert it into visible light, mitigating CAS film degradation. The aged CAS/1.0APCDs film exhibits superior morphology and mechanical properties compared to aged CAS film, maintaining 68.9% light transmission. Overall, this study introduces the development of room-temperature cured LDS layers with extended lifespan and flame retardant characteristics, offering promising applications in solar energy technology.

Intelligent electronic textiles have important application value in the field of wearable electronics due to their unique structure, flexibility, and breathability. However, the currently reported electronic textiles are still challenged by issues such as their biocompatibility, photothermal conversion, and electromagnetic wave contamination. Herein, a multifunctional biomass-based conductive coating was developed using natural carboxymethyl starch (CMS), dopamine and polypyrrole (PPy) and then further employed for constructing multifunctional intelligent electronic textiles. The prepared textiles had excellent water resistance, breathability, antioxidant and antibacterial activities, electromagnetic shielding (33 dB) as well as photothermal conversion performance, and stability. Notably, the fabricated textile could be heated from room temperature to 55 °C within 10 s under infrared radiation, and then the surface temperature of the textile could be reduced to 40 °C (τ_s = 42.05 s) within 20 s, holding great significance for research on new wearable photothermal textiles. Furthermore, the textile was utilized as a skin strain sensor, demonstrating high sensitivity to temperature, strain, photothermal and bioelectric signals and motion detection. It could monitor the physiological signal, motion control, and body temperature change of the human body in real time, offering significant potential to be applicable to integrated wearable intelligent textiles and skin bioelectronics.

Patterning soft materials with cell adhesion motifs can be used to emulate the structures found in natural tissues. While patterning in tissue is driven by cellular assembly, patterning soft materials in the laboratory most often involves light-mediated chemical reactions to spatially control the presentation of cell binding sites. Here we present hydrogels that are formed with two responsive crosslinkers-an anthracene-maleimide adduct and a disulfide linkage-thereby allowing simultaneous or sequential patterning using force and UV light. Hydrogels were formed using poly(ethylene glycol)-based crosslinkers, yielding homogeneous single networks where the mechanical properties can be controlled with crosslinker content. Compression with a PDMS stamp inked with a cysteine-terminated peptide leads to (1) force-mediated retro-Diels Alder revealing a pendant maleimide and (2) subsequent Michael-type addition of the peptide. Successful functionalization was verified through monitoring anthracene fluorescence and via cell adhesion to the immobilized peptides. The material was further functionalized using UV light to open the disulfide bond in the presence of a maleimide-terminated peptide, thereby allowing a second immobilization step. Sequential derivatization was demonstrated by adding a second cell type, yielding patterns of multiple cell populations. In this way, force and light serve as complementary triggers to create geometrically structured heterotypic cell cultures for next-generation bioassays and materials for tissue engineering.

Electrical fires pose significant threats to the lives and property safety of people. Although utilizing coatings to impart conductivity and flame retardancy to materials is convenient and reliable, traditional layer-by-layer preparation methods have the limitations of cost, convenience and scalability. Therefore, a single-layer coating that simultaneously imparts excellent conductivity and flame retardancy to materials presents broader application prospects. And good adhesion of the coating is another essential aspect. However, the trade-off between conductivity, flame retardancy, and adhesion creates huge challenges in the development of such coatings. Here, we report an ethanol-induced ammonium polyphosphate-silver (APP-Ag) gel paint to completely address the above issues. High molecular weight APP served as both a flame retardant and an adhesive, while the coordinating action of phosphate groups ensured the effective dispersion of nanosilver, and the nitrogen-containing carbon layer formed from triethanolamine and ascorbic acid at high temperature significantly enhanced the conductivity of the coating by connecting the silver nanoparticles. The coated materials could exhibit an electrical conductivity of over 200 S m^-1, with the limiting oxygen index (LOI) exceeding 60%. Meanwhile, the peak heat release rate (PHRR) and total heat release (THR) decreased by more than 30% compared to those of the untreated materials. Additionally, we utilized this gel paint to fabricate electric heating fabrics, motion sensors, and fire alarm devices. Finally, we have thoroughly explored the potential mechanisms of conductivity, flame retardancy, and adhesion of the gel coatings.

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