Flexible supercapacitors are promising energy storage devices for emerging wearable electronics. However, due to the poor mechanical strength, complicated device manufacturing process, and unsatisfactory low-temperature tolerance, their overall performance for practical applications is hindered. Herein, we report a hydrogen bonding-reinforced, dual-crosslinked poly­(vinyl alcohol), acrylic acid, and H2SO4 (PVA-AA-S) hydrogel electrolyte for all-in-one flexible supercapacitors. The PVA-AA-S hydrogel demonstrates excellent compressive/tensile properties and high ionic conductivity. It tolerates compressive stress of 0.53 MPa and is stretchable up to 500%. The hydrogel-based all-in-one supercapacitor shows promising electrochemical performance under various harsh conditions. The device energy density and power density reach up to 14.2 μWh cm–2 and 0.94 mW cm–2, respectively. Furthermore, it retains nearly 80% capacitance after being stored at −35 °C for 23 days. The excellent performance of the hydrogel electrolyte originates from its abundant strong hydrogen bonding between polymer chains and water molecules.

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A process for fabricating biodegradable polymer films from renewable feedstocks, namely, agar, alginate, and glycerol, with enhanced mechanical properties has been developed. A critical step in the process involves use of high shear stress and micromixing in a liquid thin film in an energy-efficient upsized vortex fluidic device (VFD) operating under confined-mode conditions. The upsized VFD having a 50 mm-OD diameter tube titled at 45° requires a fraction of the processing time and energy consumption relative to the standard VFD having a 20 mm-OD diameter tube titled at the same critical angle. It also overcomes difficulties of jet feed blockage and excessive gelling close to the base of the rapidly rotating tube for the high-viscosity liquid mixture when it is processed in the standard VFD operating under continuous flow for throughput competitive comparison. The enhanced mechanical properties of the polymer films (e.g., 0.14 strain) relates to the formation of a uniform solid inner microstructure and a smoother surface devoid of porosity. This is in contrast to using conventional autoclave processing, which affords films with weaker mechanical properties (e.g., 0.04 strain) having an inner microstructure with cracks and a rougher surface. In addition, the biodegradability of the polymer film produced using the upsized VFD (6 days) was not compromised relative to that produced using conventional autoclave processing. The overall facile scalable processing in generating a polymer with stronger mechanical properties is devoid of auxiliary substances and is high in green chemistry metrics.

Aramid fibers and ultra-high molecular weight polyethylene (UHMWPE) fibers lack active surface functional groups, and the surface is smooth, limiting their practical application in textile composite materials. In this study, zinc oxide nanorods were used to grow on aramid fibers surfaces, and oxygen plasma followed by treatment with a silane coupling agent was used to modify UHMWPE fibers. The effects of surface modification on the surface morphology and composition, and mechanical properties of fibers and composites were investigated. The mechanical response of interlayer hybrid textile composite materials based on modified aramid and UHMWPE fabrics was examined. The results reveal that surface roughness, active surface functional groups, and wettability that can be controlled by treatment conditions and parameters are important for improving interface adhesion. In addition, the interlayer hybridization pattern as a result of using dissimilar layer materials and altering stacking sequence has a great impact on the mechanical behavior of hybrid textile composite materials.