The rapid development of high-frequency electronic devices not only brings the rise of electronic information fields but also causes harm caused by a large amount of heat accumulation in the equipment. Herein, we build a continuous heat transfer framework formed by growing carbon nanotubes (CNTs) in an oriented boron nitride structure. The ice-dissolving complexation (IDC) method couples the orientation construction of boron nitride nanosheets (BNNS) and the surface localization of cobalt ions (Co2+) under mild conditions. The reduced Co on the surface of BNNS utilizes its catalytic ability to realize the in-situ conversion of styrene into CNTs, which link adjacent BNNS through covalent bonding to form a fluent heat transfer pathway. The oriented thermal conduction channel and low thermal resistance interface structure promote the through-plane and in-plane thermal conductivity of the composite to reach 4.83 W m−1 K−1 and 1.98 W m−1 K−1, respectively. Its light weight, compression resistance, and insulation give this composite a vaster application prospect. The design of such an efficient composite filler thermal conductivity network provides ideas for constructing of new thermal management materials.

Smart-Windows, which automatically regulate the intensity of sunlight entering the building, have attracted tremendous interest in reducing energy consumption by controlling the solar transmittance. Herein, a microgel-based double-network hydrogel (A-DN hydrogel) was prepared as flexible self-adaptable Smart-Shield to regulate sunlight. A novel thermochromic material, P(NIPAm-co-AA) microgels, was synthesized and used to construct a tough double-network hydrogel with polyacrylamide (PAAm). A-DN hydrogel, with a high solar transmittance of 87.2% at 25 °C but gradually decreased to 0% with increasing temperature to 40 °C, can intelligently select the appropriate solar transmittance according to the ambient temperature. In addition, due to the special double network structure of A-DN hydrogel and small characteristic size of microgel, A-DN hydrogel has no volume change after phase transformation and has excellent mechanical properties and high response speed. Energy Plus simulation software was used to construct the application form of simulated Smart-Shield in buildings. Simulations suggested that A-DN shield can cut off 21.04% energy consumption compared with the normal glass, and its energy saving efficiency is higher than that of commercial low-E glass (10.89%). In general, this strategy will provide new avenues for the preparation of intelligent materials with excellent mechanical properties and temperature response.

Fabricating carbon fiber/carbon nanotubes (CF/CNTs) brush is regarded as an effective way to improve its composite interfacial and mechanical properties. Different from other reports, a novel fabrication method was developed in this work. Based on Schiff base reaction, polydopamine (PDA) particle with moderate size could in-situ assist CNTs hairs to be grafted onto carbon fibers surface under agitation condition. This method can guarantee thermal stability of modified layers and facilitate the interfacial compatibility of CF/PA6 due to dynamic imine bond exchanges under high temperature (240 °C) during the injection molding. The contact angle of modified CF with PA6 decreased to 34.2° from 53.6° of the untreated-CF. The results also showed both the interfacial and mechanical properties of the composites were improved. Compared with that of the untreated-CF/PA6 composites, the interfacial shear strength, tensile strength and tensile modulus of modified-CF/PA6 were increased by nearly 64.39%, 22.14% and 21.67%, respectively. This simple modification method would provide the premise to expand it to scale-up industry production of CF reinforced thermoplastic composites.

Nacre is known for its excellent combination of strength and toughness, which is believed to be due to its complex internal structure composed of hard mineral and soft organic matter. Here, a novel strategy for fused deposition modeling (FDM) printing of nacre-like structure is presented, in which the inherent interface between filaments is considered as the soft phase and the filament as the hard phase. The nacre-like specimens with different geometric parameters are prepared and investigated by fracture test and impact test. The results show that the fracture behavior of the nacre-like specimens is controlled by the overlap ratio and the aspect ratio. The impact strength of the nacre-like specimen with a single material is up to six times that of the injection molded one. The impact resistance originates from the generation of crack deflection. The strategy of exploiting the inherently weak interface of FDM printed materials provides a novel approach to the structural design of 3D printed composites.

3D printed short carbon fiber reinforced thermoplastic (SCFRTP) composites are attracting intensive attention because of their advantages such as easy molding, recyclability, etc. The microstructure characteristics including the internal defects, and fiber distributions of 3D printed SCFRTP composites have significant impacts on their performances. In this work, the special engineering plastic polyetheretherketone (PEEK) was used as the matrix, and the 3D printed SCFRTP composites with the short carbon fiber contents of 1 wt% to 10 wt% were prepared and characterized. Then, the probability density distributions of short carbon fibers and micro-void defects were calculated. The micro influencing factors on the tensile properties of the 3D printed SCFRTP composites were studied. This paper provides experimental data for the in-depth analyses and design of 3D printed SCFRTP composites.

Inspired by the multi-level physiological structure of wood cell wall, a bionic method accomplished by annular thickening of cell wall by polymer was proposed to improve the mechanical performances of plantation wood. The thickening mechanism and the contribution of annular thickening of cell wall to the mechanical performances of plantation wood was analyzed. Results indicated that wood cell wall could be annularly thickened by the modification system prepared with water-soluble vinyl monomers and organic solvent. The flexural, compressive and impact strengths of plantation wood were synchronously improved after the treatment. The modulus of rupture of the prepared wood with 22.4% weight percentage gain reached up to 95.7 MPa which was higher than the TB 17 requirement based on the Chinese National Standard (GB 50206). The thickening degree which could be controlled by adjusting modifier concentration was closely related to the mechanical performance of treated wood.

This paper uses experimental, numerical and analytical methods to investigate the bistable behavior of a curved bistable composite slit tube (Bi-CST). Using the vacuum bag method, two specimens were prepared and bistable experiments were performed. Two Finite Element Models (FEMs) were presented to model the bistable deformation process. Based on the minimum energy principle and three failure criteria, an analytical model to determine the bistable behavior of the curved Bi-CST was proposed, including the strain energy, geometric configuration and stress level. Analytical and numerical results agreed well with experimental results.

Polymethyl methacrylate (PMMA) cement is widely used in bone surgery for its good plasticity, chemical inertness, and excellent mechanical properties. Because of the high transparency of pure PMMA bone cement under X-ray imaging, it is necessary to add radiopacifiers such as barium sulfate. However, the interface compatibility between barium sulfate and PMMA is poor, leading to poor mechanical properties of the cement. In addition, the leaching of toxic barium ions significantly reduced the biocompatibility of the cement. In this study, a corrosion-resistant, insoluble ceramic, tungsten carbide (WC), is used as a radiopacifier. When the WC content is 10 wt%, the compressive strength is approximately 90 MPa without affecting the continuity of PMMA. The modified bone cement with 10 wt% WC showed superior radiopacity to that of commercial PMMA bone cement containing 30 wt% BaSO4. Moreover, the addition of WC greatly decreased the cytotoxicity of conventional PMMA. Our study proposed a novel PMMA cement with enhanced radiopacity and biocompatibility, showing great potential to be applied in the orthopedic field.

As flexible electronic devices become increasingly compact and powerful, they generate more heat, necessitating efficient thermal management to ensure their reliable operation. Flexible substrates, which are essential components of these devices, often struggle to dissipate heat effectively due to their inherent low thermal conductivity. To overcome this challenge, the development of highly thermally conductive flexible substrates is crucial. By employing the electrospinning technique, large-area flexible films were successfully fabricated in this study. The film exhibited a notable in-plane thermal conductivity, reaching its maximum value at 38.4 Wm−1K−1. The film demonstrated its superior performance at a filler concentration of 50 wt%, displaying a thermal conductivity of 28.6 Wm−1K−1, a tensile strength of 27.8 MPa, and an elongation of 8.1%. Furthermore, the film exhibited exceptional flexibility, satisfying the requirements for next-generation flexible substrates. The present study unveils innovative findings concerning the fabrication of expansive and exceptionally thermally conductive flexible substrates, as well as the management of performance in filler-based macroscopic assemblies.

Carbon nanotubes (CNTs) are widely used for strengthening and toughening of resin matrix. However, the improvement of resin matrix toughness can't be effectively transferred to carbon fiber reinforced polymer (CFRP) composites due to the “fiber filtration effect”. Here, short carbon nanotubes (SCNTs, average length <2 μm) were added to the epoxy resin and then used as the matrix of CFRP. The test results showed that 0.5 wt% SCNTs is the optimal mass fraction for matrix toughening, which enhanced the maximum strain, maximum stress and toughness of the epoxy resin by 43.3%, 10.1% and 65.9%, respectively, and the mode I interlaminar fracture toughness of resultant CFRPs was increased by as much as 86.7%. The superior interlaminar toughening efficiency of SCNTs can be ascribed to their smaller size, which enables them to penetrate into the tiny gaps of carbon fiber yarns, thus not only effectively avoiding the “fiber filtration effect” and making them evenly distributed in the matrix, but also strengthening the interfaces between epoxy resin and carbon fibers.

PTFE nanofiber membrane, as an effective supplement to biaxial stretched PTFE membrane, suffers from low modulus and poor structural stability. In this study, the PTFE porous membrane with high modulus and structural stability was designed and achieved via the in-situ interlocking and anchoring strategy by co-electrospinning polyacrylonitrile (PAN) into PTFE matrix. During the sintering process, the continuous flexible PTFE nanofibers formed, while PAN nanofibers was pre-oxidized to create a stable trapezoidal structure. The effects of pre-oxidized PAN (OPAN) nanofibers' content and diameter on the morphology and structure of the PTFE/OPAN composite nanofiber membrane were investigated in detail. Results showed that the introduction of OPAN nanofiber effectively improve the modulus and structural stability of PTFE nanofiber membrane. The Young's modulus and tensile strength of the composite nanofiber membrane were over 50 MPa and 2 MPa, which were 1166% and 80% higher than that of pure PTFE nanofiber membrane, respectively. These results of this work would contribute to solve the defects of PTFE nanofiber membrane's low modulus and poor structural stability, and then expand its application scope.

Owing to the poor interfacial bonding between reinforcing phases and Ti3SiC2 matrix, the Ti3SiC2 matrix composites enhanced by the reinforcements still exhibited inadequate mechanical and tribological properties. In this paper, the Ti3SiC2 matrix composites reinforced by the 10, 20, and 30 vol%TiC0.4 addition were fabricated using spark plasma sintering (SPS) at 1400 °C. The effect of TiC0.4 addition on microstructure and properties of the Ti3SiC2 matrix composites was investigated. The results showed that TiC0.4 addition not only improved the interfacial bonding between reinforcing phases and Ti3SiC2 matrix by promoting the decomposition of Ti3SiC2, but also formed TiCx hard phase, improving the mechanical and tribological properties of the Ti3SiC2 matrix composites. With 20 vol% of TiC0.4 amount, the TiC0.4-Ti3SiC2 composite demonstrated the optimal comprehensive properties, the bulk density, relative density, hardness, fracture toughness, friction coefficient, and wear rate at room temperature reached the values of 4.6 g/cm3, 99.6%, 12.01 GPa, 6.18 MPa m1/2, 0.63, and 4.59×10−7 mm3N−1m−1, respectively. The wear mechanism of the TiC0.4-Ti3SiC2 composites was mainly ascribed to adhesive wear at room temperature.

The impact of TiO2 and Fe20Ni80 coating layer on roughness, magnetic properties, giant magneto-impedence (GMI) effect and dipole interactions of FINEMET/TiO2/Fe20Ni80 composite ribbons were investigated systematically. The TiO2 layer can effectively tune transverse magnetic structure and GMI ratio of composite ribbons. More TiO2 coating layer thickness deteriorates the magnetic properties, and dipole interactions decrease owing to the distance between FINEMET ribbon and Fe20Ni80 layer increases. When the thickness of TiO2 is 100 nm, composite ribbons exhibit small roughness of 8.5 nm, a large GMI ratio of 63% at 0.8 MHz, dipole field of 1.0 Oe, which is superior to other semiconductor composite ribbons. The variation in GMI ratio can be explained as the change of transverse permeability, and the decrease of magnetic dipole interactions can be explained as the change of distance between the FINEMET ribbon and Fe20Ni80 layer. The results show that the combination of semiconductor and magnetic materials can realize the miniaturization of magnetic sensing, and it has a guiding role in the development of GMI effect and magnetic interactions theory of composite materials.

Wind turbine generators with high power will develop increasingly to achieve an ambitious goal of carbon peaking and carbon neutrality, demanding urgently larger and lighter blades with long service life and high mechanical strength. Here we fabricate renewable composites with thiol-functionalized carbon fibers (TCF) and epoxy-ended hyperbranched polymers (HT12), exhibiting a competitive property. Compared with the corresponding performance of diglycidyl ether of bisphenol A (DGEBA)/pristine carbon fibers composites, the tensile strength, tensile modulus, flexural strength, flexural modulus, and interlaminar shear strength of HT12/TCF composites are increased by 89.84%, 154.55%, 217.89%, 366.62%, and 376.52%, respectively. The service life of the HT12/TCF composites is about 200 years at 40 °C by simulating environmental experiments of acid rain and seawater resistance, being much longer than DGEBA/carbon fibers of about 20 years. Additionally, the HT12/TCF composites can be rapidly decomposed into oligomers and carbon fibers under mild conditions, which can be reused to prepare HT12/TCF composites by reacting directly with formaldehyde via a condensation between the amino group and the aldehyde group. After recycling twice, the composites still maintain high mechanical strength, suggesting highly efficient renewability of carbon fibers and epoxy resins. This research provides a sustainable approach for preparing high-performance environmentally-friendly epoxy resin/carbon fiber composites capable of uprecycling, and well-balancing service life and performance.

To solve the disadvantages of polyethylene (PE) separator for lithium-ion batteries (LIBs), such as low polarity, poor electrolyte wettability, and severe thermal dimensional shrinkage, the composite solution of poly(ether ketone) (PEEK) and carbon nanoparticles, which was obtained by the carbonization of nanocellulose (NCC) in the sulfuric acid solution, were applied to modify the PE separator to prepare Janus composite separator (PE/PC) with high porosity. PE/PC exhibited high dimensional thermal stability with a shrinkage rate of 53% after 0.5 h of treatment at 150 °C, and a higher electrolyte loading rate (196.3%) than PE. Accordingly, it also presented excellent battery performance. The discharge capacity of the cell using PE separator was 148 mAh g−1 after 100 cycles, while that with PE/PC separator were 155 mAh g−1 after 200 cycles. The initial efficiency of discharge-charge of PE/PC with 2% NCC (PE/PC2) was as high as 97.6%. This should be related to the high ion conductivity (1.21 × 10−3 S cm−1). Furthermore, the carbon nanoparticles effectively provided abundant secondary oxidation reaction sites for the active material between the separator and cathode, allowing the free diffusion of Li+, thus also reducing the charge transfer resistance and improving the battery performance.

High-temperature proton exchange membranes (HT-PEMs) doped with phosphoric acid (PA) can achieve high proton conduction at high phosphoric acid doping level (ADL). However, polybenzimidazole (PBI) membranes have problems with PA loss, poor mechanical properties, and other issues at high ADL. Herein, PAF-1-NH2 was obtained through an amination of porous aromatic frameworks with an ultrahigh specific surface area (PAF-1), and APAF-1 was prepared by vacuum injection of PA on PAF-1-NH2 to increase the ADL through the high basic site amount and specific area. APAF-1/OPBI composite HT-PEMs was prepared by solution casting method. The composite membrane maintained superior mechanical properties, high proton conductivity and low dimensional swelling ratio (166.2%) even with a high PA doping rate (328.5%), due to the rigid structure of APAF-1 and the strong interfacial interaction between APAF-1 and OPBI. The mechanical strength and proton conductivity of the 10%APAF-1/OPBI were 20.86 MPa and 0.107 S cm−1 at 200 °C, respectively, which was about 2.43 times that of the OPBI membrane (0.044 S cm−1). When the catalyst Pt dosage was only 0.3 mg cm−2, the peak power density of the H2/O2 fuel cell at 180 °C was 366.6 mW cm−2. Therefore, this work presented a new approach for preparing HT-PEMs with excellent comprehensive properties.

Waterproof breathable membranes (WBMs) are widely employed in various fields. However, the construction of fluorine-free WBMs with excellent waterproofness using simple strategies remains a challenge. Herein, we report waterproof breathable polyethylene terephthalate (PET) fibrous membranes embedded with fluorine-free hydrophobic polydimethylsiloxane (PDMS) via a simple one-step electrospinning combined with heat treatment techniques. The resultant PET/PDMS membranes with vigorous hydrophobic channels, small apertures and high porosity were constructed by in-situ doping of PDMS, which endowed them with excellent water resistance of 86.9 kPa, good moisture permeability of 5100 g m−2 d−1, desirable air permeability of 6.97 mm s−1, and enhanced mechanical strength of 6.27 MPa. The obtained nanofiber WBMs can be used as an exceptional additional product for a variety of existing applications.

A negative temperature coefficient (NTC) thermistor with thermal sensing and control capabilities was manufactured by adopting form stable phase change materials (PCMs). The incorporation of PCMs expanded their potential uses by providing a stable and continuous circuit. The PCMs underwent a nearly isothermal phase transition process, which lasted for a long time without significant temperature fluctuations. To hold the pure PCM and prevent leakage during melting and cooling processes, a graphene aerogel was employed as a supporting material. Compared with microsphere PCM composite, the graphene aerogel had a high porosity. The PCM composite retained over 98 wt% of the working material for thermal energy. The NTC thermistor probe was inserted into the PCM composite to construct a thermal sensible device. The PCM surrounded NTC thermistor exhibited an excellent thermal stability and could maintain the output current in the circuit. These findings suggest that the form stable PCM composite can be utilized in thermal controllable systems to prevent overcurrent and safeguard electronic devices.

In this work, an oxide fiber-reinforced oxide matrix (oxide/oxide) composite was fabricated by a lamination process using a sol-based slurry. The density and the porosity of the oxide/oxide composite was 2.72 g/cm3 and 32.5%, respectively. The oxide matrix had a porous microstructure, and its elastic modulus was much lower than that of the oxide fiber. The as-received composite had a high flexural strength of 280.6 ± 9.3 MPa, a high interlaminar shear strength of 18.1 ± 0.7 MPa and a high fracture toughness of 7.6 ± 0.6 MPa m1/2. Fiber pull-out and crack deflection during fracture process were observed. The high elastic modulus ratio of fiber to matrix is critical to trigger toughening mechanisms of the composite.

Magnetic soft composites with programmable magnetization patterns are highly desirable for diverse applications due to their multimodal magnetic response and locomotion. Despite substantial progress achieved in magnetic programming approaches, reprogrammable magnetization using low magnetic fields is still in development and challenging. Here, we report a one-step multi-direction magnetic reorientation strategy capable of reprogramming magnetization patterns in soft composites consisting of an elastomer matrix and magnetized ferromagnetic microparticles encapsulated by a phase-change polymer. Our approach is first based on the overall heating of these soft composites to achieve polymer phase transition, and then use magnet arrays to locally regulate the magnetic field distribution to achieve magnetic reorientation and programmable magnetization. Importantly, this approach allows us to reconstruct the desired magnetization patterns by reheating and redesigning the applied magnetic field. Using this approach, we numerically and experimentally demonstrate that multimodal magnetization and deformation patterns of millimeter-level strip-shaped and multi-arm phase-change soft composites can be achieved without changing the composite structure and the externally applied magnetic field. Furthermore, we demonstrate its functional applications in developing a multistate circuit switching, as well as a flexible magnetic recording that can present a variety of information such as numbers, letters, and face-based patterns.