Advanced Composites and Hybrid Materials最新文献

Elastic conductors play a crucial role in the fabrication of wearable electronic devices and human–computer interaction devices. Among the various candidates for elastic conductors, hydrogels, featuring 3-D swollen macromolecular networks, exhibit exceptional stretchability and biocompatibility. Notably, physical hydrogels based on poly (vinyl alcohol) (PVA), which contains a substantial number of reactive groups (-OH groups), stand out due to their remarkable biocompatibility, superior mechanical properties, and chemical stability. This review focuses on recent advancements in the composite strategy, preparation, and current applications of PVA-based conductive composite hydrogels. Firstly, PVA-based conductive hydrogels are classified based on various conductive treatments: (i) introduction of conductive fillers to the PVA with a single network structure; (ii) introduction of conductive fillers to the PVA with double/multiple network structures (e.g., PVA/carboxymethylcellulose, PVA/poly(acrylamide)); (iii) creation of double-network PVA hydrogel combined with conductive polymers including poly(3,4-ethylene-dioxythiophene)/poly(styrenesulfonate), poly(aniline), poly(pyrrole); (iv) addition of ions to a pure PVA network; (v) addition of ions to the PVA with double network structures (e.g., PVA/sodium alginate, PVA/hydroxyethylcellulose). This review includes a comparative analysis of different conductive hydrogel systems. Secondly, PVA-based conductive hydrogels with diverse functions, such as strain sensing, shape memory, antifreeze properties, transparency, and pH response, are thoroughly reviewed. Thirdly, the latest advancements in the applications of PVA-based conductive hydrogels are demonstrated, including flexible super-capacitors, human–computer interaction devices, and triboelectric nanogenerator sensors. Finally, a summary of the current state of development and critical issues with PVA conductive hydrogels is provided, along with an outlook on how to address each.

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Systematic review on PVA conductive hydrogels: outlines preparation strategies and applications in flexible electronic devices.

Since ancient times, humans have used wood as a building material due to its unique properties including porosity, anisotropy, biodegradability, and easy processing. Wood-based composites have been extensively studied in order to meet the performance requirements of the wood during use. However, the environmental burdens are steadily increasing due to the pollution in the synthesis of wood-based composites. At present, it has become a mainstream development trend to use environmentally friendly materials as raw materials and use adhesive-free bonding technology to prepare wood-based composites. Based on this green production, various environmentally friendly functional additives are widely mixed into raw materials to endow advanced wood-based composites with new practical functions such as electromagnetic shielding, antibacterial, and flame retardant. Hence, this paper summarizes the types of traditional wood-based composites and the pollution problems that exist in the preparation and application process, focusing on the green preparation technology and performance advantages of advanced wood-based composites. Among them, the adhesive-free hot-pressed technology is the most environmentally friendly method in the green preparation technology. Meanwhile, this paper looks forward to the development direction of advanced wood-based composites with new functions processed by green preparation technology. Furthermore, it will be upgraded towards the research of multi-functional integrated advanced wood-based composites in the future.

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High-entropy CoCrFeMnNi alloy/aluminide-laminated composites were produced via the hot pressing diffusion sintering method at 1000 ℃. The results revealed that the aluminide structure layer based on the Al₁₃(Cr, Mn, Fe, Co, Ni)₄ phase first transforms into Al₈(Cr, Mn, Fe, Co, Ni)₅ phases with a trigonal crystal structure and then gradually transitions into Al(Cr, Mn, Fe, Co, Ni) phases with a B2 cubic crystal structure under high-temperature annealing. During high-temperature annealing, the elements Ni, Co, and Fe exhibit higher diffusion rates and diffusion amounts in the aluminide layer. The transformation of the aluminide layer is mainly influenced by the diffusion behavior of these elements. The absence of an oxidation interface barrier during high-temperature annealing results in multiple diffusion mechanisms, leading to the predominance of lattice diffusion and interface diffusion, which control the growth kinetic of the Al(Cr, Mn, Fe, Co, Ni) phase layer. The hardness indentation of the B2-Al(Cr, Mn, Fe, Co, Ni) phases, obtained by high-temperature annealing, shows no cracks and exhibits a multi-slip system characteristic of ductile aluminum compounds. This ductile behavior helps to reduce the deformation resistance in the hard and brittle layer and decreases the likelihood of delamination failure during plastic deformation. The bending strength of high-entropy/aluminide-layered (HAL) composite materials after high-temperature annealing reaches 1000 MPa, with the main energy dissipation modes being the plastic deformation of the ductile layer and fracture of the hard and brittle layer. Dynamic impact failure forms mainly include plastic deformation and delamination, with impact strength and energy consumption reaching 2317 MPa and 4750 J/mm³, respectively. This study provides phase formation sequence and dynamic mechanical properties of high-entropy CoCrFeMnNi/B2 structure aluminide-laminated composites which proved to be a new type of composites with good impact resistance.

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With the rapid development of industry, this leads to sewage discharge and air pollution that seriously affect human health and ecosystem. Therefore, environmental remediation has attracted wide attention in academia in recent years. Covalent organic frameworks, a new type of porous materials, have been widely developed in this field due to their advantages of easy modification and high specific surface area. Here, we summarize the research progress of covalent organic framework materials in the field of environmental remediation in recent years, including sewage treatment, antibacterial application, atmospheric water extraction, iodine vapor adsorption, and flue gas separation. The synthesis strategies, structures, morphologies, and modification methods of covalent organic frameworks were discussed as a whole to show how their properties and long-term use were affected, and the structure–activity relationship between molecular structures and application properties of covalent organic frameworks was summarized. This review is of great significance for researchers to fully understand the development status and future trends of covalent organic frameworks in the field of environmental remediation.

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Covalent organic frameworks with structured channels for easy molecular design have great potential applications in the field of environmental remediation.

Recently, many efforts have been devoted to studying early-stage fire-warning materials (EFWMs). Among those, thermoelectric effect-based EFWM (TE-EFWMs) are particularly attractive because they are self-powered and intrinsically sensitive to temperature. However, none of the reported fire-warning response times of TE-EFWMs can reach 1.0 s. Herein, flame-retardant composite cotton fabrics with speedy and repeatable fire warning function (denoted as CF-TE-FR) were constructed by in-situ polymerized polypyrrole (PPy) doped with P-toluenesulfonic acid (PTSA) and a flame retardant composite layer composed of sodium montmorillonite (MMT) and ammonium polyphosphate (APP). The fire warning performance of CF-TE-FR was effectively enhanced through PTSA doping, and the fire warning response time was shortened with an increasing concentration of PTSA. The fire warning indicator could be triggered as fast as 0.8 s when the molar ratio of PTSA to pyrrole monomer reached 1:3. Meanwhile, all the CF-TE-FR samples could release the fire-warning signals repeatedly. This work proposes a facile approach to the fabrication and application of organic thermoelectric polymer-based materials with ultrafast fire-warning response, repeatable fire-warning capability, and excellent flame retardancy.

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Flame-retardant cotton fabrics based on the thermoelectric effect of polypyrrole demonstrate speedy and repeatable fire warning function.

The successful employment of lithium metal substituting for the conventional graphite anode can promote a significant leap in the cell energy density for its ultrahigh theoretical specific capacity, the lowest electrochemical voltage, and low density. However, the notorious lithium dendrite growth, low Coulombic efficiency, and massive volume expansion seriously fetter its practical usage. Adopting three-dimensional (3D) structured scaffolds with large specific surface area and porous structure to stabilize lithium metal inside has been regarded as one of the most effective strategies to enhance the electrochemical performance of Li metal and eliminate the safe concerns. Herein, the current progress of composite scaffolded Li metal anodes is reviewed according to the host types, lithiophilic sites, structure, and the preparation technology to stimulate the development of Li metal batteries. Furthermore, to boost the commercialization of the composite scaffolded Li metal anode, the perspectives and critical challenges of the scaffolded Li metal anodes toward practical usage have also been prospected.

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3D scaffolds joint with lithiophilic sites enable highly stable scaffolded Li metal and high-performance practical Li metal batteries.

Daidzein, a naturally occurring source of estrogenic isoflavones, holds significant promise for various applications in food and drug development. Therefore, to realize efficient and precise daidzein separation, we synthesized a magnetic surface molecularly imprinted polymer (Daidzein/SMIPs) via free radical-initiated polymerization via magnetic surface molecular imprinting technology. The adsorption capacity of the Daidzein/SMIPs for daidzein at an initial concentration of 300 µg·mL⁻¹ reached 18.44 mg·g⁻¹ within 20 min at 298 K. Even after nine adsorption-desorption cycles, the adsorption capacity remained high (81.42% of the initial adsorption capacity). Furthermore, the Daidzein/SMIPs exhibited exceptional selectivity for daidzein, with an imprinting factor of 1.83 and selection coefficients (K) of 1.94, 2.43, 2.63, and 1.66 for structurally similar competing molecules such as naringin, quercetin, diosmetin, and alizarin, respectively. In practical applications, isolating daidzein from real daidzein tablets using the Daidzein/SMIPs resulted in high recoveries of 88.09 to 98.12% with excellent precision (relative standard deviation of 1.51–1.02%). Therefore, the constructed Daidzein/SMIPs feature immense potential for targeted daidzein isolation applications.

Negative permittivity (ε′ < 0), considered a supernormal property, has broadened the range of electromagnetic parameters. It provides a new principle for the design of high-end electronic devices, such as optical circuits, high-integrated chips, and electromagnetic point connectors. Negative permittivity is previously achieved by periodic array and is considered an artificial property. In recent years, the feasibility of realizing negative permittivity was demonstrated in the materials by adjusting the composition and microstructure of materials, especially in percolative composites consisting of conductive fillers and insulative matrix, which then has rapidly attracted great attention of researchers working in the field of materials science and engineering. In this review, we introduced the mechanisms of negative permittivity and summarized the recent research progress of negative permittivity performance in percolative composites with different compositions and microstructures. Besides, we introduced the potential applications of negative permittivity materials in dielectric capacitors and electromagnetic shielding. Finally, we put forward the challenges and prospects of negative permittivity performance in percolative composites, indicating the trend and focus of future research.

Peroxymonosulfate (PMS)-assisted visible photocatalytic degradation of organic pollutants via graphitic carbon nitride (g-C₃N₄) is a promising and environmentally friendly technology. But pristine g-C₃N₄ still suffers from limited visible light utilization and low charge carrier mobility. Herein, g-C₃N₄ doped by C derived from lignin (LCN) was synthesized via a straightforward calcination process involving a physical blend of lignin and melamine, and its photocatalysis and PMS-assisted photocatalysis under visible light for typical organic pollutant tetracycline hydrochloride (TC) were studied. The experimental results show that due to the incorporation of C atoms by replacing bridging N atoms in g-C₃N₄, LCN has improved visible light utilization and enhanced charge transfer. Under the assistance of PMS, LCN-1 (1 wt% lignin in g-C₃N₄) exhibits a markedly high TC degradation efficiency, with a degradation rate 6.74 times that of pristine g-C₃N₄. In addition, the main radicals and reaction mechanisms in both systems were proposed through free radical quenching experiments and electron paramagnetic resonance signal. This work offers insights into the development of low-cost C-doped g-C₃N₄, using sustainably sourced lignin, and further demonstrates its superior efficiency in photocatalytic degradation of TC coupled with PMS activation.

Hematite (α-Fe₂O₃) is considered a highly promising candidate material for photoelectrochemical water splitting (PEC-WS) due to its suitable band gap and band edge location. Nevertheless, enhancing PEC-WS performance through the surface construction of low-cost, highly efficient, and stable electrocatalysts still remains a challenge. This work presents a facile strategy to fabricate α-Fe₂O₃ photoanodes modified with the metal–organic framework films doped with iron-group elements (Fe, Co, and Ni), which forms abundant active sites and leverage bimetallic synergistic effects. The optimal photocurrent density of FTO/Sn@α-Fe₂O₃/MIL-125/Co photoanode achieves 1.97 mA/cm² at 1.23 V_RHE, which is 2.3 times that of the pure α-Fe₂O₃ photoanode. The on-set potential exhibits a cathodic shift of 0.1 V. The MIL-125 catalyst with Co doping exhibits the most excellent PEC-WS performance among the three dopants (Fe, Co, and Ni), which can be primarily attributed to more abundant active sites, the lower photogenerated carrier recombination, and the enhanced charge separation and transfer efficiency.

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