Tin dioxide nanotubes with N-doped carbon layer (SnO₂/N-C NTs) were synthesized through a MoO₃ nanorod-based sacrificial template method, dopamine polymerization and calcination process. Applied to the Li-ion battery, SnO₂/N-C NTs exhibited excellent electrochemical properties, with a first discharge capacity of 1722.3 mAh·g⁻¹ at 0.1 A·g⁻¹ and a high capacity of 1369.3 mAh·g⁻¹ over 100 cycles. The superior electrochemical performance is ascribed to the N-doped carbon layer and tubular structure, which effectively improves the electrical conductivity of the composites, accelerates the migration of Li⁺ and electrons, and alleviates the volume change of the anode to a certain extent.

Nitrogen-doped carbon-coated hollow SnS₂/NiS (SnS₂/NiS@N–C) microflowers were obtained using NiSn(OH)₆ nanospheres as the template via a solvent-thermal method followed by the polydopamine coating and carbonization process. When served as an anode material for lithium-ion batteries, such hollow SnS₂/NiS@N–C microflowers exhibited a capacity of 403.5 mAh·g⁻¹ at 2.0 A·g⁻¹ over 200 cycles and good rate performance. The electrochemical reaction kinetics of this anode was analyzed, and the morphologies and structures of anode materials after the cycling test were characterized. The high stability and good rate performance were mainly due to bimetallic synergy, hollow micro/nanostructure, and nitrogen-doped carbon layers. The revealed excellent electrochemical energy storage properties of hollow SnS₂/NiS@N–C microflowers in this study highlight their potential as the anode material.

A hydrophilic hyperbranched polyester (poly (tetramethylol acetylenediurea (TA)-CO-succinyl chloride) (PTS)) was proposed to be used as an organic additive in aqueous ZnSO₄ electrolyte to achieve a highly reversible zinc/manganese oxide battery. It is found that the zinc symmetric battery based on the 2.0 wt.% PTS/ZnSO₄ electrolyte showed a long cycle stability of more than 2400 h at 1.0 mA·cm⁻², which is much longer than that including the blank ZnSO₄ electrolyte (140 h). Furthermore, the capacity retention of the Zn||MnO₂ full cells employing the 2.0 wt.% PTS/ZnSO₄ electrolyte remained 85% after 100 cycles at 0.2 A·g⁻¹, which is much higher than 20% capacity retention of the cell containing the blank ZnSO₄ electrolyte, and also greater than 59.6% capacity retention of the cell including the 10.0 wt.% TA/ZnSO₄ electrolyte. By using 2.0 wt.% PTS/ZnSO₄ electrolytes, the capacity retention of the Zn||MnO₂ full cells even reached 65% after 2000 cycles at a higher current density of 1.0 A·g⁻¹. It is further demonstrated that the PTS was firmly adsorbed on the zinc anode surface to form a protective layer.

The incorporation of mechanophores, motifs that transform mechanical stimulus into chemical reaction or optical variation, allows creating materials with stress-responsive properties. The most widely used mechanophore generally features a weak bond, but its cleavage is typical an irreversible process. Here, we showed that this problem can be solved by folding–unfolding of a molecular tweezer. We systematically studied the mechanochromic properties of polyurethanes with cyano-substituted oligo(p-phenylene) vinylene (COP) tweezer (DPU). As a control experiment, a class of polyurethanes containing only a single COP moiety (MPU) was also prepared. The DPU showed prominent mechanochromic properties, due to the intramolecular folding–unfolding of COP tweezer under mechanical stimulus. The process was efficient, reversible and optical detectable. However, due to the disability to form either intramolecular folding or intermolecular aggregation, the MPU sample was mechanical inert.

Hemostatic dressings with multiple functions are superior to current hemostatic dressings for use in the complex situation of emergency accidents. In particular, the existing dressings lack consideration for the prevention of hypothermic shock after massive hemorrhage. In this study, gelatin (GN) and oxidized pectin (OP) were used for Schiff base cross-linking, and then polyvinyl alcohol (PVA) solution mixed with hemostatic caffeic acid (CA) was introduced to obtain aerogel substrate material (CB) after lyophilization. Polydimethylsiloxane (PDMS) and silver nanowires (Ag NWs) were used to construct a hydrophobic layer, an antibacterial layer and an infrared reflective layer on both sides of CB to prepare a multifunctional aerogel wound dressing with heat preservation, antifouling, hemostasis and antibacterial properties (PDMS-Ag NW-CB). The results showed that the infrared transmittance of PDMS-Ag NW-CB is almost 0, so that thermal energy loss from the body is minimized. The contact angles with water and blood are 129° and 120°, respectively, which have the effect of antifouling. This dressing can absorb blood quickly within 10 min, adhere to and gather platelets, and achieve hemostasis. It has good antibacterial and biocompatibility. Therefore, PDMS-Ag NW-CB has great potential in application to emergency treatment.

In the research for the safe and efficiently antibacterial cotton fabrics to minimize risk for human health, an organic–inorganic hybrid material of ZnO nanoparticles (NPs) and quaternary ammonium salt (QAS) was employed to modify cotton fabrics by a dipping–padding–drying method. The synergistic effects of ZnO NPs and QAS on the structure and antibacterial properties of cotton fabrics were studied in detail. Results displayed that the QAS and ZnO NPs were immobilized firmly in cotton fabric by the formation of chemical covalent bonds and silica gel structure. ZnO/QAS/cotton had a good inhibitory effect on the growth of E. coli and S. aureus, with superior antibacterial efficiency of >99.99%. ZnO/QAS/cotton preserved good mechanical property, water absorbability, and limpness. We also provided a detailed analysis of antibacterial mechanism for the hybrid materials. The contact mechanism and the Zn²⁺ release were considered as the main mechanisms for the ZnO/QAS/cotton, while the reactive oxygen species (ROS) generation only had a little contribution to the antibacterial activity. In short, the excellent integrated properties endowed the hybrid cotton fabrics as potential application in many fields, like healthcare, food packaging.

Sn-based materials are considered as a kind of potential anode materials for lithium-ion batteries (LIBs) owing to their high theoretical capacity. However, their use is limited by large volume expansion deriving from the lithiation/delithiation process. In this work, amorphous Sn modified nitrogen-doped porous carbon nanosheets (ASn-NPCNs) are obtained. The synergistic effect of amorphous Sn and high edge-nitrogen-doped level porous carbon nanosheets provides ASn-NPCNs with multiple advantages containing abundant defect sites, high specific surface area (214.9 m²·g⁻¹), and rich hierarchical pores, which can promote the lithium-ion storage. Serving as the LIB anode, the as-prepared ASn-NPCNs-750 electrode exhibits an ultrahigh capacity of 1643 mAh·g⁻¹ at 0.1 A·g⁻¹, ultrafast rate performance of 490 mAh·g⁻¹ at 10 A·g⁻¹, and superior long-term cycling performance of 988 mAh·g⁻¹ at 1 A·g⁻¹ after 2000 cycles with a capacity retention of 98.9%. Furthermore, the in-depth electrochemical kinetic test confirms that the ultrahigh-capacity and fast-charging performance of the ASn-NPCNs-750 electrode is ascribed to the rapid capacitive mechanism. These impressive results indicate that ASn-NPCNs-750 can be a potential anode material for high-capacity and fast-charging LIBs.

In order to provide a biomimetic natural extracellular matrix microenvironment with excellent mechanical capacity for tissue regeneration, a novel porous hybrid glycidyl methacrylate-modified silk fibroin/poly(L-lactic acid-co-ε-caprolactone)–polyethylene glycol diacrylate (SFMA/P(LLA-CL)–PEGDA) hybrid three-dimensional (3D) nanofibrous scaffolds was successfully fabricated through the combination of 3D nanofibrous platforms and divinyl PEGDA based photocrosslinking, and then further improved water resistance by ethanol vapor post-treatment. Scanning electron microscopy and micro-computed tomography results demonstrated significant PEGDA hydrogel-like matrices bonded nanofibers, which formed a 3D structure similar to that of “steel bar (nanofibers)‒cement (PEGDA)”, with proper pore size, high porosity, and high pore connectivity density. Meanwhile, the hybrid 3D nanofibrous scaffolds showed outstanding swelling properties as well as improved compressive and tensile properties. Furthermore, these hybrid 3D nanofibrous scaffolds could provide a biocompatible microenvironment, capable of inducing the material‒cell hybrid and regulating human umbilical vein endothelial cells proliferation. They thus present significant potential in tissue regeneration.

Processing biomaterials into porous scaffolds for bone tissue engineering is a critical and a key step in defining and controlling their physicochemical, mechanical, and biological properties. Biomaterials such as polymers are commonly processed into porous scaffolds using conventional processing techniques, e.g., salt leaching. However, these traditional techniques have shown unavoidable limitations and several shortcomings. For instance, tissue-engineered porous scaffolds with a complex three-dimensional (3D) geometric architecture mimicking the complexity of the extracellular matrix of native tissues and with the ability to fit into irregular tissue defects cannot be produced using the conventional processing techniques. 3D printing has recently emerged as an advanced processing technology that enables the processing of biomaterials into 3D porous scaffolds with highly complex architectures and tunable shapes to precisely fit into irregular and complex tissue defects. 3D printing provides computer-based layer-by-layer additive manufacturing processes of highly precise and complex 3D structures with well-defined porosity and controlled mechanical properties in a highly reproducible manner. Furthermore, 3D printing technology provides an accurate patient-specific tissue defect model and enables the fabrication of a patient-specific tissue-engineered porous scaffold with pre-customized properties.

Despite more than a decade of study, there are still significant obstacles to overcome before graphene can be successfully produced on a large scale for commercial use. Chemical oxidation of graphite to produce graphene oxide (GO), followed by a subsequent reduction process to synthesize reduced graphene oxide (rGO), is considered the most practical method for mass production. Microorganisms, which are abundant in nature and inexpensive, are one of the potential green reductants for rGO synthesis. However, there is no recent review discussing the reported microbial reduction of GO in detail. To address this, we present a comprehensive review on the reduction of GO by a range of microorganisms and compared their efficacies and reaction conditions. Also, presented were the mechanisms by which microorganisms reduce GO. We also reviewed the recent advancements in using microbially reduced GO as the anode and cathode material in the microbial fuel cell (MFC) and algal biophotovoltaics (BPV), as well as the challenges and future directions in microbial fuel cell research.

Developing high-activity and low-cost catalysts is the key to eliminate the limitation of sluggish anodic oxygen evolution reaction (OER) during electrocatalytic overall water splitting. Herein, Ni‒Fe/black phosphorous (BP) composites are synthesized using a simple three-electrode system, where exfoliation of bulky BP and synthesis of NiFe composites are simultaneously achieved. Under light illumination, the optimized Ni‒Fe/BP composite exhibits excellent photoelectrocatalytic OER performance (e.g., the overpotential is 58 mV lower than a commercial RuO₂ electrocatalyst at a current density of 10 mA·cm⁻²). The electron transfer on this composite is proved to follow a Ni‒BP‒Fe pathway. The electronic structure of this Ni‒Fe/BP composite is effectively regulated, leading to optimized adsorption strength of the intermediate OH* and improved intrinsic activity for the OER. Together with active sites on the support, this Ni‒Fe/BP composite possesses abundant electrochemical active sites and a bug surface area for the OER. The introduction of light further accelerates the electrocatalytic OER. This work provides a novel and facile method to synthesize high-performance metal/BP composites as well as the approaches to reveal their OER mechanisms.

In this study, a novel diethylene triamine penta(methylene phosphonic acid) (DTPMPA)- and graphene oxide (GO)-modified superhydrophobic anodized aluminum (DGSAA) coating was fabricated. The obtained coatings were characterized by scan electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Raman analysis. After immersion in the supersaturated CaCO₃ solution for 240 h, the scaling mass of the DGSAA coating is only 50% of that of the SAA coating. The excellent anti-scaling performance of the DGSAA coating comes from three barriers of the air layer, the DTPMPA:Ca²⁺ chelate, and the lamellar GO, as well as the further active anti-scaling of DTPMPA:Ca²⁺ at the coating–solution interface. DTPMPA and GO at the surface of the DGSAA coating exhibit an insertion structure. In the electrochemical impedance spectroscopy measurement, the impedance modulus of the DGSAA coating is three orders-of-magnitude higher than that of the anodized aluminum. The synergistic effect of DTPMPA stored in the porous structure of anodized aluminum and the barrier protection of superhydrophobicity and GO contributes to the excellent comprehensive performance of the DGSAA coating. This research provides a new perspective for designing anti-scaling and anti-corrosion superhydrophobic bi-functional coatings.

As a new type of luminescent material, carbon dots (CDs) have attracted increased attention for their superior optical properties in recent years. However, solid-state fluorescent CDs, especially with red emission, are still a major challenge. Here, CDs with solid-state red emission were synthesized by co-doping of N and B using the one-step microwave method. The CD powder exhibits excitation-independent solid-state red fluorescence without any dispersion matrices, with optimum solid-state fluorescence wavelength of 623 nm. The hydrogen bonding interaction in CDs is helpful for solid-state fluorescence of CDs. The I_G/I_D value of CDs reaches up to 3.49, suggesting their very high graphitization degree, which is responsible for their red emission. In addition, CDs show the concentration-induced multicolor emission, which is attributed to the decreased energy gap in the high concentrated CD solution. To exploit their concentration-dependent emission, CDs with changing ratio in matrices are applied as a color-converting layer on ultraviolet chip to fabricate multicolor light-emitting diodes with light coordinates of (0.33, 0.38), (0.41, 0.48), (0.49, 0.44), and (0.67, 0.33), which belong to green, yellow, orange, and red light, respectively.

The catalytic conversion of biomass platform chemicals using abundant non-noble metal nanocatalysts is a challenging topic. Here, high-density cobalt oxide nanoparticles loaded on biomass-derived porous N-doped carbon (NC) was fabricated by a tandem hydrothermal pyrolysis and mild nitrate decomposition process, which is a green and cheap preparation method. The Co₃O₄ nanoparticles with the average size of 12 nm were uniformly distributed on the porous NC. The nanocomposites also possessed large surface area, high N content, good dispersibility in isopropanol, and furfural absorbability. Due to these characteristics, the novel cobalt nanocatalyst exhibited high catalytic activity for producing furfuryl alcohol, yielding 98.7% of the conversion and 97.1% of the selectivity at 160 °C for 6 h under 1 bar H₂. The control experiments implied that both direct hydrogenation and transfer hydrogenation pathways co-existed in the hydrogenation reaction. The excellent catalytic activity of Co₃O₄@NC was attributed to the cooperative effects of porous NC and Co₃O₄ nanoparticles. This approach provides a new idea to design effective high-density non-noble metal oxide nanocatalysts for hydrogenation reactions, which can make full use of sustainable natural biomass.

Carbon aerogels derived from biomass have low specific capacity due to the underutilized structure, limiting their application in high-performance supercapacitors. In this work, the hierarchical nickel sulfide/carbon aerogels from liquefied wood (LWCA-NiS) were synthesized via a simple two-step hydrothermal method. Benefitting from the unique 3D coral-like network structure of LWCA, self-assembled NiS nanowires with the dandelion-like structure showed high specific surface (389.1 m²·g⁻¹) and hierarchical pore structure, which increased affluent exposure of numerous active sites and structural stability, causing superior energy storage performance. As expected, LWCA-NiS displayed high specific capacity (131.5 mAh·g⁻¹ at 1 A·g⁻¹), good rate performance, and highly reversible and excellent cycle stability (13.1% capacity fading after 5000 cycles) in the electrochemical test. Furthermore, a symmetrical supercapacitor using LWCA-NiS-10 as the electrode material delivered an energy density of 12.7 Wh·kg⁻¹ at 299.85 W·kg⁻¹. Therefore, the synthesized LWCA-NiS composite was an economical and sustainable candidate for the electrodes of high-performance supercapacitors.

Among various metal chalcogenides, metal oxides and phases of copper sulfide, copper(II) sulfide (covellite, CuS) nanostructures have enjoyed special attentiveness from researchers and scientists across the world owing to their complicated structure, peculiar composition and valency, attractive and panoramic morphologies, optical and electrical conductivity, less toxicity, and biocompatibility that can be exploited in advanced and technological applications. This review paper presents a brief idea about crystal structure, composition, and various chemical methods. The mechanism and effect of reaction parameters on the evolution of versatile and attractive morphologies have been described. Physical properties of CuS and its hybrid nanostructures, such as morphology and optical, mechanical, electrical, thermal, and thermoelectrical properties, have been carefully reviewed. A concise account of CuS and its hybrid nanostructures’ diverse applications in emerging and recent applications such as energy storage devices (lithium-ion batteries, supercapacitance), sensors, field emission, photovoltaic cells, organic pollutant removal, electromagnetic wave absorption, and emerging biomedical field (drug delivery, photothermal ablation, deoxyribonucleic acid detection, anti-microbial and theranostic) has also been elucidated. Finally, the prospects, scope, and challenges of CuS nanostructures have been discussed precisely.

As a structural and functional material with excellent properties, ceramics play an extremely important role in a wide range of industries, including life and production. To expand the range of applications for ceramic materials, ceramics are often joined to metals and then used. Among the physical and chemical joining methods of ceramics to metals, the AMB method is efficient and simple, suitable for industrial applications, and has been a hot topic of research. However, due to the problems of residual stresses caused by the large difference in thermal expansion coefficients between ceramic and metal brazing, composite fillers have become a very worthwhile solution by regulating the physical properties of the brazing material and improving the weld structure. This review describes the wetting principle and application of Ag‒Cu‒Ti active metal filler in the field of ceramic joining, with emphasis on the current stage of composite filler, and discusses the influence on the former brazing properties and organization after the introduction of dissimilar materials.

Flexible strain sensors have been extensively used in human motion detection, medical aids, electronic skins, and other civilian or military fields. Conventional strain sensors made of metal or semiconductor materials suffer from insufficient stretchability and sensitivity, imposing severe constraints on their utilization in wearable devices. Herein, we design a flexible strain sensor based on biphasic hydrogel via an in-situ polymerization method, which possesses superior electrical response and mechanical performance. External stress could prompt the formation of conductive microchannels within the biphasic hydrogel, which originates from the interaction between the conductive water phase and the insulating oil phase. The device performance could be optimized by carefully regulating the volume ratio of the oil/water phase. Consequently, the flexible strain sensor with oil phase ratio of 80% demonstrates the best sensitivity with gauge factor of 33 upon a compressive strain range of 10%, remarkable electrical stability of 100 cycles, and rapid resistance response of 190 ms. Furthermore, the human motions could be monitored by this flexible strain sensor, thereby highlighting its potential for seamless integration into wearable devices.

Sintering resistant noble metal nanoparticles are critical to the development of advanced catalysts with high activity and stability. Herein, we reported the construction of highly dispersed Pd nanoparticles loaded at the inner wall of ZrO₂ hollow spheres (Pd@HS-ZrO₂), which shows improved activity and thermal stability over references in the Pd-ZrO₂ (catalyst-support) system. Even after 800 °C high temperature calcination, the Pd nanoparticles and ZrO₂ hollow spheres did not undergo morphological changes. The Pd@HS-ZrO₂ manifests batter catalytic activity and thermal stability than the counterpart Pd/ZrO₂ catalysts. In comparison to Pd/ZrO₂-800, Pd@ZrO₂-800 exhibits a 25°C reduction in the temperature required for complete conversion of CO. The enhanced catalytic activity and thermal stability of Pd@HS-ZrO₂ can be attributed to the nanoconfinement effect offered by the 10 nm wall thickness of the ZrO₂ hollow spheres, which suppresses the coarsening of the Pd nanoparticles (active center for catalysis).

It is still a challenge to prepare a water- and polymer-based electrospun air filter film with high efficiency filtration, low pressure drop, and good mechanical properties. To address this issue, polyvinyl alcohol (PVA) was employed as the main material, mixing polyethyleneimine (PEI), bamboo-based activated carbon (BAC) and cellulose nanocrystal (CNC) to construct the air filter film by electrostatic electrospinning. In this system, the negatively charged BAC and CNC are fixed in the system through bonding with the positively charged PEI, showing a double adsorption effect. One is the mechanical filtration of the porous network structure constructed by PVA@PEI electrospun nanofibers, and the other is the electrostatic adsorption of PM2.5 on the surface of BAC and CNC. It is significant that the resulting composite air filter displays a high filtration efficiency of 95.86%, a pressure drop of only 59 Pa, and good thermal stability. Moreover, the introduced methyltrimethoxysilane (MTMS) endows it with good water-resistance. Given these excellent performances, this system can provide theoretical and technical references for the development of water- and polymer-based electrospun air filter film.

Pore characteristics have been identified as key design parameters for osteoimmunomodulation. The strategy reported here is to create an appropriate immune microenvironment by regulating pore characteristics of scaffolds, thereby promoting early angiogenesis and enhancing osteogenesis. A series of collagen/nano-hydroxyapatite (Col/nHAP) composite scaffolds with ordered lamellar structures and different layer spacings were prepared by mimicking the ordered lamellar topology of the bone matrix. Our research indicated that the layer spacing and ordered topology of the scaffold exerted an important influence on phenotype transformation of macrophages and the secretion of angiogenic factors. The Col/nHAP-O(135) with large layer spacing not only supported cell attachment and diffusion in vitro, but also promoted early angiogenesis by timely switching from M1 to M2 macrophage phenotype. In vivo data showed that the layer spacing and the ordered structure of the scaffold synergistically regulated the inflammatory response and triggered macrophages to secrete more angiogenesis related cytokines. Col/nHAP-O(135) considerably promoted the neovascularization and new bone formation in the defect site, indicating that Col/nHAP-O(135) could significantly enhance the osteogenic activity of stem cells with the involvement of macrophages.

Malignant neoplasms represent a significant global health threat. To address the need for accurate diagnosis and effective treatment, research is underway to develop therapeutic nanoplatforms. Iron oxide nanoparticles (NPs), specifically Fe₃O₄ NPs have been extensively studied as potential therapeutic agents for cancer due to their unique properties including magnetic targeting, favorable biocompatibility, high magnetic response sensitivity, prolonged in vivo circulation time, stable performance, and high self-metabolism. Their ability to be integrated with magnetic hyperthermia, photodynamic therapy, and photothermal therapy has resulted in the widespread use of Fe₃O₄ NPs in cancer diagnosis and treatment, making them a popular choice for such applications. Various methods can be employed to synthesize magnetic Fe₃O₄ NPs, which can then be surface-modified with biocompatible materials or active targeting molecules. Multifunctional systems can be created by combining Fe₃O₄ NPs with polymers. By combining various therapeutic approaches, more effective biomedical materials can be developed. This paper discusses the synthesis of Fe₃O₄ NPs and the latest research advances in Fe₃O₄-based nanotherapeutic platforms, as well as their applications in the biomedical field.

Autonomous self-healing hydrogels were achieved through a dynamic combination of hydrogen bonding and ferric ion (Fe³⁺) migration. N,N′-methylenebis (acrylamide) (MBA), a cross-linking agent, was added in this study. Poly(acrylic acid) (PAA)/Fe³⁺ and PAA–MBA/Fe³⁺ hydrogels were prepared by introducing Fe³⁺ into the PAA hydrogel network. The ionic bonds were formed between Fe³⁺ ions and carboxyl groups. The microstructure, mechanical properties, and composition of hydrogels were characterized by field emission scanning electron microscopy and Fourier transform infrared spectroscopy. The experimental results showed that PAA/Fe³⁺ and PAA–MBA/Fe³⁺ hydrogels healed themselves without external stimuli. The PAA/Fe³⁺ hydrogel exhibited good mechanical properties, i.e., the tensile strength of 50 kPa, the breaking elongation of 750%, and the self-healing efficiency of 82%. Meanwhile, the PAA–MBA/Fe³⁺ hydrogel had a tensile strength of 120 kPa. These fabricated hydrogels are biocompatible, which may have promising applications in cartilage tissue engineering.

Polyurethane (PU) foams are widely used in thermal management materials due to their good flexibility. However, their low thermal conductivity limits the efficiency. To address this issue, we developed a new method to produce tannic acid (TA)-modified graphene nanosheets (GTs)-encapsulated PU (PU@GT) foams using the soft template microstructure and a facile layer-by-layer (L-B-L) assembly method. The resulting PU@GT scaffolds have ordered and tightly stacked GTs layers that act as three-dimensional (3D) highly interconnected thermal networks. These networks are further infiltrated with polydimethylsiloxane (PDMS). The through-plane thermal conductivity of the polymer composite reaches 1.58 W·m⁻¹·K⁻¹ at a low filler loading of 7.9 wt.%, which is 1115% higher than that of the polymer matrix. Moreover, the mechanical property of the composite is ~2 times higher than that of the polymer matrix while preserving good flexibility of the polymer matrix owing to the retention of the PU foam template and the construction of a stable 3D graphene network. This work presents a facile and scalable production approach to fabricate lightweight PU@GT/PDMS polymer composites with excellent thermal and mechanical performance, which implies a promising future in thermal management systems of electronic devices.

Flexible humidity sensors are widely used in many fields, such as environmental monitoring, agricultural soil moisture content determination, food quality monitoring and healthcare services. Therefore, it is essential to measure humidity accurately and reliably in different conditions. Flexible materials have been the focusing substrates of humidity sensors because of their rich surface chemical properties and structural designability. In addition, flexible materials have superior ductility for different conditions. In this review, we have summarized several sensing mechanisms, processing techniques, sensing layers and substrates for specific humidity sensing requirements. Aadditionally, we have sorted out some cases of flexible humidity sensors based on different functional materials. We hope this paper can contribute to the development of flexible humidity sensors in the future.

Few-layers WS₂ was obtained through unique chemical liquid exfoliation of commercial WS₂. Results showed that after the exfoliation process, the thickness of WS₂ reduced significantly. Moreover, the NiFe₂O₄ nanosheets/WS₂ composite was successfully synthesized through a facile hydrothermal method at 180 °C, and then proven by the analyses of field emission scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The composite showed a high specific surface area of 86.89 m²·g⁻¹ with an average pore size of 3.13 nm. Besides, in the three-electrode electrochemical test, this composite exhibited a high specific capacitance of 878.04 F·g⁻¹ at a current density of 1 A·g⁻¹, while in the two-electrode system, the energy density of the composite could reach 25.47 Wh·kg⁻¹ at the power density of 70 W·kg⁻¹ and maintained 13.42 Wh·kg⁻¹ at the higher power density of 7000 W·kg⁻¹. All the excellent electrochemical performances demonstrate that the NiFe₂O₄ nanosheets/WS₂ composite is an excellent candidate for supercapacitor applications.

The layer-structured composites were built by the dielectric and insulating layers composed of polyvinylidene fluoride (PVDF) and low-density polyethylene (LDPE) composites containing barium titanate (BT) to modulate the dielectric and energy storage properties of the composites. The simulations on the interface models for molecular dynamics and the geometric models for finite element analysis were performed together with the experimental characterization of the morphology, dielectric, and energy storage properties of the composites. The results revealed that polyethylene as an insulating layer played a successful role in modulating dielectric permittivity and breakdown strength while BT particles exerted positive effects in improving the miscibility between the composed layers and redistributing the electric field. The strong interface binding energy and the similar dielectric permittivity between the PVDF layer and the BT20/LDPE layer made for the layer-structured composites with a characteristic breakdown strength (E_b) of 188.9 kV·mm⁻¹, a discharge energy density (U_d) of 1.42 J·cm⁻³, and a dielectric loss factor (tanδ) of 0.017, which were increased by 94%, 141%, and decreased by 54% in comparison with those of the BT20/PVDF composite, respectively.

Herein, a novel visible-light-responsive photocatalyst with high efficiency was firstly synthesized at room temperature. The mild synthetic method resulted in a uniform spherical triazine-based covalent organic framework (TrCOF2) with ultra-high specific surface area as well as chemical stability. Due to the synergistic effect between the self-assembled uniform spherical structure and the abundant triazine-based structure, photoelectron–hole pairs were efficiently separated and migrated on the catalysts. On this basis, TrCOF2 was successfully applied to efficiently degrade bisphenol A (BPA). More than 98% of BPA was deraded after 60 min of visible light treatment, where the active specie of •O₂ ⁻ played a vital role during the degradation of BPA. The holes of TrCOF2 could produce O₂ by direct reaction with water or hydroxide ions. Simultaneously, photoelectrons can be captured by O₂ to generate •O₂ ⁻. Moreover, density functional theory (DFT) calculations proved the outstanding ability of the exciting electronic conductivity. Remarkably, a reasonable photocatalytic mechanism for TrCOF2 catalysts was proposed. This research can provide a facile strategy for the synthesis of TrCOFs catalysts at room temperature, which unfolds broad application prospects in the environmental field.

Electrospun nanofibers with highly efficient photothermal/electrothermal performance are extremely popular because of their great potential in wearable heaters. However, the lack of necessary wearable properties such as high mechanical strength and quick response of electrospun micro/nanofibers seriously affects their practical application. In this work, a technical route combining electrospinning and surface modification technology is proposed. The 3-triethoxysilylpropylamine-polyacrylonitrile@copper sulfide (K-PAN@CuS) composite fabric was achieved by modifying the original electrospinning PAN fiber and subsequently loading CuS nanoparticles. The results show that the break strength of the K-PAN@CuS fabric was increased by 10 times compared to that of the original PAN@CuS fabric. Furthermore, the saturated temperature of the K-PAN@CuS fabric heater could reach 116 °C within 15 s at a relatively low voltage of 3 V and 120.3 °C within 10 s under an infrared therapy lamp (100 W). In addition, due to its excellent conductivity, such a unique structural design enables the fiber to be closely attached to the human skin and helps to monitor human movements. This K-PAN@CuS fabric shows great potential in wearable heaters, hyperthermia, all-weather thermal management, and in vitro physical therapy.

Nitrogen atom doping has been found to enhance the electrochemical performance of porous carbon (PC). In this study, hollow tubular nitrogen-doped porous carbon (N/PC) was synthesized using polyvinylpyrrolidone as the carbon–nitrogen source and fibrous brucite as the template through carbonization. The effects of nitrogen and argon protective atmospheres on the nitrogen content, the specific surface area (SSA), and electrochemical properties of N/PC were investigated. The results showed that compared with N/FBC-Ar, N/FBC-N₂ prepared in nitrogen protective atmosphere had a higher nitrogen content and a larger proportion of pyrrolic nitrogen (N-5) and pyridinic nitrogen (N-6). N/FBC-N₂ displayed a specific capacitance (C) of 194.1 F·g⁻¹ at 1 A·g⁻¹, greater than that of N/FBC-Ar (174.3 F·g⁻¹). This work reveals that the nitrogen doping with a higher nitrogen content in nitrogen protective atmosphere is more favorable. Furthermore, a larger proportion of pyrrolic nitrogen and pyridinic nitrogen in the doped nitrogen atoms significantly enhances the electrochemical performance.