Multifunctional ultraelastic helical conductive yarn for motion detection and human-machine interaction

Abstract

Featured with intrinsic lightweight, great flexibility, and easy integration into functional textiles or devices, the stretchable conductive fiber has attracted much attention in the realm of wearable electronics. However, the conductive fibers encounter a troublesome “trade-off” between high conductivity and large elasticity under large deformation, which restricts their widespread applications. Herein, we designed a multifunctional highly elastic helical conductive yarn (HCY) by electrospinning polyurethane (PU) nanofibers, polydopamine (PDA)-assisted silver nanoparticles (AgNPs) deposition and over-twisting. The introduction of a PDA mediated layer fosters strong bond between the conductive AgNPs and the elastic PU nanofibers matrix, showcasing robust structural stability and electrical performance. The hierarchically interlocked conductive structure confers high electrical conductivity to the stretchable HCY, enabling it to withstand large mechanical deformation, which achieves good recoverability within a range of 700 %, great durability (40000 times at deformation of 200 %) and maximum conductive tensile elongation up to 1200 %. Furthermore, the HCY also features excellent Joule-heating ability, great antibacterial performance, and functions as a rapid-response strain sensor (GFmax = 9.82), which is ideal for detecting human motion and enhancing human–machine interactions. This work provides a new path for developing advanced stretchable conductive materials, which is of great significance for versatile ultraelastic wearable electronic devices.