Facile fabrication of flame‐retardant and conductive cotton fabric via layer‐by‐layer assembly for human motion detection

Abstract

Flexible piezoresistive pressure sensors have great application potential in many emerging fields such as electronic skin, artificial intelligence and human healthcare. However, most of the sensors are flammable, which will easily initiate fire hazard in case of short circuit. Herein, a flame‐retardant and conductive cotton fabric (CF) was fabricated for piezoresistive pressure sensor by layer‐by‐layer (LBL) assembly of branched polyethyleneimine (b‐PEI) modified halloysite nanotubes (HNTs), phytic acid (PA) and graphene oxide (GO) and the subsequent thermal reduction of GO. The composite coating layer endowed the obtained CF with excellent flame retardancy. The limiting oxygen index of the CF reached 32.72% and the char length after vertical burning test was only 3.8 cm, attributing to the physical barrier role of the HNTs and graphene nanosheets as well as the phosphorus‐nitrogen synergism between PA and b‐PEI. The CF‐based piezoresistive pressure sensor exhibited fast and accurate response, good signal stability and fatigue resistance (3000 loading‐unloading cycles) and was able to be applied for detecting human motions including pulse beat, pronunciation and various physical activities. The preparation method in this work is simple, and the piezoresistive pressure sensor shows great application prospect in the field of flexible electronics with high safety.