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Inspired by the ultralight and structurally robust spider webs, flexible nanofibril‐assembled aerogels with intriguing attributes have been designed for achieving promising performances in various applications. Here, conductive polyimide nanofiber (PINF)/MXene composite aerogel with typical “layer‐strut” bracing hierarchical nanofibrous cellular structure has been developed via the freeze‐drying and thermal imidization process. Benefiting from the porous architecture and robust bonding between PINF and MXene, the PINF/MXene composite aerogel exhibits an ultralow density (9.98 mg cm−3), intriguing temperature tolerance from ‐50 to 250 °C, superior compressibility and recoverability (up to 90% strain), and excellent fatigue resistance over 1000 cycles. The composite aerogel can be used as a piezoresistive sensor, with an outstanding sensing capacity up to 90% strain (corresponding 85.21 kPa), ultralow detection limit of 0.5% strain (corresponding 0.01 kPa), robust fatigue resistance over 1000 cycles, excellent piezoresistive stability and reproductivity in extremely harsh environments. Furthermore, the composite aerogel also exhibits superior oil/water separation properties such as high adsorption capacity (55.85 to 135.29 g g−1) and stable recyclability due to its hydrophobicity and robust hierarchical porous structure. It is expected that the designed PINF/MXene composite aerogel can supply a new multifunctional platform for human bodily motion/physical signals detection and high‐efficient oil/water separation.

Superhydrophobic polymer foams are a good candidate for oil absorption because of their lightweight and tunable porosity and have promising applications in the long-term application of oil−water separation. However, developing a facile and green strategy to fabricate pure polymer foams with superhydrophobicity and eco-friendliness for large-scale oil−water separation remains a challenge. Here, a facile template-free water-assisted thermally impacted phase separation approach combined with skin peeling for the fabrication of superhydrophobic and eco-friendly pure poly(lactic acid) (PLA) foam for oil−water separation is proposed for the first time. The PLA foam with special micro-and nanostructures possesses a water contact angle of 151°, and the maximum saturated adsorption capacity is 31.5 g/g. More importantly, during the continuous oil−water pumping experiment, the foam has an efficiency of 98% and could maintain for more than 15 h, showing a promising prospect for cleaning large-scale oil pollution.

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The schematic of metamaterials applied in wireless power transfer.

As a crucial component of data terminal acquisition devices, flexible strain sensor has shown promising applications in numerous fields, such as healthcare, bodynet, the intelligent traffic system, and the robotic system. For stretchable strain sensor, it remains a huge challenge to realize a fine balance of wide detection range and high sensitivity. Here, an electrically conductive carbon nanotube/thermoplastic polyurethane fiber with a multilayered, hollow, and monolith structure, accompanying high stretchability (up to 476% strain) and low density (about 0.46 g/cm) is fabricated through a facile coaxial wet-spun assembly strategy. The as-prepared fibers with a designed independent sensitive zone and flexible supporting zone possess an ultralow percolation threshold (0.17 wt %) and a tunable size and structure. This structure endows the fiber with a good integration of adequate flexibility, suitable strength, and high elongation at break for wearable electronics. The fiber, which is then assembled as a strain sensor, realizes the perfect combination of the wide sensing range (>350% strain), high sensitivity (gauge factor (GF) = 166.7 at 350% strain), and excellent working durability (>10 000 cycles). Our sensor could also detect small compressing deformations (0.35% N at 0.025-50 N) by capturing the resistance change of the fiber with superior stability. The highly stretchable, light weight, and multilayered fiber with the designed hollow-monolith structure provides a new route for the preparation of high-performance wearable electronics.

The significant fire hazards on the polymer-based thermal interface materials (TIM) used in electronic devices are but often neglected. Also, high filler loading with the incident deterioration of mechanical, thermal, and processing properties limits the further application of the traditional polymer-based TIMs. In this work, a ternary TIMs with epoxy resin (EP) matrix, silver nanowires (AgNWs), and a small amount of flame-retardant functionalized graphene (GP-DOPO) were proposed to address the above questions. Briefly, a facile "branch-like" strategy with a polymer as the backbone and flame-retardant molecule as the branch was first used to functionalize reduced graphene oxide (RGO) toward increasing the flame-retardant grafting ratio and RGO's compatibility in matrix, and the resulted GP-DOPO was then in situ introduced into the EP/AgNW composites. As expected, the incorporation of GP-DOPO (2 wt %) can increase the thermal conductivity to 1.413 W/(m K) at a very low AgNW loading (4 vol %), which is 545 and 56% increments compared to pure EP and EP/AgNW, respectively. The prominent improvement in thermal conductivity was put down to the synergetic effect of AgNW and GP-DOPO, i.e., the improving dispersion and bridging effect for AgNWs by adding GP-DOPO. Moreover, the high flame-retardant grafting amount and the excellent compatibility of GP-DOPO resulted in a strong catalytic charring effect on EP matrix, which further formed a robust protective char layer by combining the AgNW and graphene network. Therefore, the flame retardancy of EP/AgNW was significantly improved by introducing GP-DOPO, i.e., the peak heat release rate, total heat release and total smoke production reduced by 27.0, 32.4, and 30.9% reduction compared to EP/AgNW, respectively.

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