Hierarchically Core‐Dual Sheath Stretchable Conductive Yarns for On‐Demand Thermoregulation and Wearable Strain Sensing

Abstract

Abstract Stretchable conductive yarn‐based textiles are crucial for smart wearable electronics, achieving both exceptional conductivity and stretchability at industrial scales remains challenging. Herein, a continuous strategy is proposed for manufacturing stretchable conductive wrapped yarns (SCWYs) with hierarchically core‐dual sheath architecture through industrialized hollow‐spindle wrap spinning. The elastane filament (EF) core provides SCWYs with excellent stretchability and resilience, and a silver‐plated nylon filament (SPNF) sub‐outer layer enables multifunctional characteristics. The linen yarn (LY) outermost layer provides skin‐contact comfort. The elastane draw ratio serves as a processing parameter that critically influences the tunable stretchability of SCWYs. Optimally, the exceptional stretchability and robust cyclic durability (200% strain at 3.0 draw ratio) of SCWY stem from its interlaced‐helical architecture and draw‐ratio tunability of EF. The coupled effects of initially tight helix of SPNF and the introduction of EF component create a strain‐dependent response profile, attenuating the responsiveness to low‐to‐moderate tensile strains versus higher strains (i.e., 150% and beyond). Furthermore, the SCWY also exhibits superior programmable electrothermal behavior, antibacterial efficacy, tactile comfort, environment‐friendly recyclability, and functions as a rapid‐response strain sensor for full‐range tracking. This work presents a scalable manufacturing protocol for stretch‐tunable conductive yarns that enable advanced multifunctional wearable electronics with seamless textile integration.