A. Hazarika, B.K. Deka, D.Y. Kim, H.W. Park
Ulsan National Institute of Science and Technology,
Keywords: Kevlar fiber, wearable device, dynamic thermoregulation, flexibility, mechanical properties
Summary:Personal thermoregulation is a major goal in the development of smart, wearable devices, regardless of climate conditions, and can reduce the demand for power from external sources. An immense amount of energy is consumed for heating indoor environments in cold weather, while body heat is continually radiated into the surroundings. Maintaining comfortable personal thermal conditions while outdoors in the summer is also challenging. Here, we have developed a novel personal thermoregulatory (PTM) device inspired by the thermoregulation mechanism of endotherms. The PTM device features a smart heating/cooling mechanism that responds to changing climatic conditions. The devices were fabricated with woven Kevlar fiber (WKF) containing perpendicularly grown silver nanoparticle-decorated branched cobalt molybdenum phosphide nanowires (Ag@CoxMo1-xP). These fibers were spin-coated with reduced graphene oxide (rGO) dispersed in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) or PEDOT:PSS/poly(N-isopropylacrylamide) (PNIPAM). Ag@CoxMo1-xP coupled with rGO promoted efficient Joule heating, attaining 76oC at 2.1 V, in WKF/PEDOT:PSS.