Bioinspired ultra-stretchable and anti-freezing conductive hydrogel fibers with ordered and reversible polymer chain alignment.

High-performance stretchable conductive fibers are desired for the development of stretchable electronic devices. Here we show a simple spinning method to prepare conductive hydrogel fibers with ordered polymer chain alignment that mimics the hierarchically organized structure of spider silk. The as-prepared sodium polyacrylate hydrogel fiber is further coated with a thin layer of polymethyl acrylate to form a core-shell water-resistant MAPAH fiber. Owing to the coexistence and reversible transformation of crystalline and amorphous domains in the fibers, MAPAH fibers exhibit high tensile strength, large stretchability and fast resilience from large strain. MAPAH fiber can serve as a highly stretchable wire with a conductive hydrogel core and an insulating cover. The stretchability and conductivity of the MAPAH fiber are retained at -35 °C, indicating its anti-freezing property. As a prime example of stretchable conductive fibers, MAPAH fibers will shed light on the design of next generation textile-based stretchable electronic devices.