Multifunctional and highly stretchable electronics based on silver nanowires / wrap yarn composite for wearable strain sensor and heater
Stretchable and wearable electronics, as a well-researched engineering frontier, can be applied in human motion detecting, thermal therapy, personal healthcare monitoring and smart human–machine interaction. In this work, a multifunctional textile-based electronics with combined strain sensing and heating capabilities was successfully fabricated from silver nanowire / wrap yarn through a facile and scalable fabrication approach. The wearable electronics possessed favorable sensitivity, high conductivity (resistance≈ 36 Ω cm-1) as well as large strain range (tolerable strain up to 200%). When the functionalized yarn served as a strain sensor, it exhibited fast, reproducible and stable response under various tensile loadings. In addition, the strain sensor showed favorable electromechanical reliability and durability (1000 cycles). Furthermore, the strain sensor can detect large-scale human movements when directly attached to elbow, wrist and knee. When the composite served as a heater, it presented high heating temperature, homogeneous temperature distribution, fast thermal response, low operation voltage (2V-6V) and stability in repeated and long-term use. Based on the superior performance, the wearable electronics holds tremendous prospect for human motion monitoring, health tracking and thermotherapy.