Self‐Bondable and Stretchable Conductive Composite Fibers with Spatially Controlled Percolated Ag Nanoparticle Networks: Novel Integration Strategy for Wearable Electronics

Abstract Advances in electronic textiles (E‐textiles) for next‐generation wearable electronics have originated from making a balance between electrical and mechanical properties of stretchy conductive fibers. Despite such progress, the trade‐off issue is still a challenge when individual fibers are woven and/or stretched undesirably. Time‐consuming fiber weaving has limited practical uses in scalable E‐textiles. Here, a facile method is presented to fabricate ultra‐stretchable Ag nanoparticles (AgNPs)/polyurethane (PU) hybrid conductive fibers by modulating solvent diffusion accompanied by in situ chemical reduction and adopting a tough self‐healing polymer (T‐SHP) as an encapsulation layer. First, the controlled diffusivity determines how formation of AgNPs is spatially distributed inside the fiber. Specifically, when a solvent with large molecular weight is used, the percolated AgNP networks exhibit the highest conductivity (30 485 S cm⁻¹) even at 300% tensile strain and durable stretching cyclic performance without severe cracks by virtue of the efficient strain energy dissipation of T‐SHP encapsulation layers. The self‐bondable properties of T‐SHP encapsulated fibers enables self‐weavable interconnects. Using the new integration, mechanical and electrical durability of the self‐bonded fiber interconnects are demonstrated while stretching biaxially. Furthermore, the self‐bonding assembly is further visualized via fabrication of a complex structured E‐textile.