A flexible carboxymethyl chitosan/aminated CNTs/cotton fabric piezoresistive sensor with flame retardancy and fire warning

Herein, a highly flame-retardant and sensitive fire-alarm piezoresistive sensor (HFSFPS) was developed by coating carboxymethyl chitosan (CCS)/aminated carbon nanotubes (ACNTs) on cotton fabric through a layer-by-layer (LBL) assembly method. Benefitting from the synergistic flame-retardant layer formed by CSS and ACNTs, the flame was effectively isolated and the air supply was blocked. During combustion, the heat-sensitive behavior of ACNTs connected to the carbonized CSS to from a new electron transport pathway. As a result, the resistance of the HFSFPS dropped sharply and triggered the fire-alarm system within 3 s. Moreover, the HFSFPS exhibited excellent pressure monitoring ability with sensitivities of 2 kP a−1 (from 0 kPa to 19.1 kPa) and 0.6 kP a−1 (from 19.1 kPa to 46.5 kPa), respectively. The HFSFPS could be integrated with firefighting suits or electronic skins for monitoring the movements of firefighters and the operation of equipment, and is expected to be widely used in the field of intelligent firefighting.