Large-scale production of highly responsive, stretchable, and conductive wrapped yarns for wearable strain sensors

Abstract

Abstract Stretchable conductive yarns have received crucial attention in the direction of wearable electronics. Integration of ordinary yarns with conductive phase endows additional functions such as strain sensing. Herein, highly responsive, stretchable, conductive wrapped yarns with different wrapping densities were prepared, using elastane filament as core, co-wrapped with silver-plated nylon filament (SPNF) and polyester filament. It was found that a wrapping density of 750 T·m −1 was an optimal alternative, taking into account tensile and elastic-related properties, keeping the elastane draw ratio constant. By virtue of the helical-interlaced structure and spiral configuration of wrapping components, the optimized yarn can bear up to nearly 200% strain and exhibit larger-strain cyclic robustness. By incorporating SPNF into the wrapped yarn, it can serve as a stretchable conductor, and it is also able to precisely detect body motion (e.g. finger bending) with high responsiveness (shorter response time). Such functional yarns hold tremendous prospects for wearable electronics.