A\nBiaxially Stretchable and Self-Sensing Textile Heater\nUsing Silver Nanowire Composite

Abstract

Wearable\nheaters have garnered significant attention from academia\nand industry for their great potential in thermotherapy. Silver nanowire\n(AgNW) is a promising conductive material for flexible and stretchable\nelectrodes. Here, a resistive, biaxially stretchable heater based\non AgNW composite is reported for the first time, where a AgNW percolation\nnetwork is encased in a thin polyimide (PI) film and integrated with\na highly stretchable textile. AgNW/PI is patterned with a 2D Kirigami\nstructure, which enables constant resistance under a large tensile\nstrain (up to uniaxial 100% strain and 50% biaxial strain). The heater\ncan achieve a high temperature of ∼140 °C with a low current\nof 0.125 A, fast heating and cooling rates of ∼16.5 and ∼14.1\n°C s^–1, respectively, and stable performance\nover 400 heating cycles. A feedback control system is developed to\nprovide constant heating temperature under a temperature change of\nthe surrounding environment. Demonstrated applications in applying\nthermotherapy at the curvilinear surface of the knee using the stretchable\nheater illustrate its promising potential for wearable applications.