High Sensitivity, Wide Range Pressure Sensor Based on Layer-by-Layer Self-Assembled MXene/Carbon Black@Polyurethane Sponge for Human Motion Monitoring and Intelligent Vehicle Control

Abstract

Flexible pressure sensors with high sensitivity, low cost, lightweight, and convenience are of significance in the field of human movement monitoring and sensing. This article demonstrated a piezoresistive pressure sensor prepared by layer-by-layer (LbL) self-assembly of MXene and carbon black (CB) on a polyurethane (PU) sponge. The electronegativity of MXene and the electropositive of CB enable them to combine more stably. The assembled sensor achieves reliable repeatability (over 3700 cycle testing), high sensitivity (−5.26 kPa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula> ), wide sensing range (0–240 kPa), acceptable response time (300/300 ms), and good reproducibility under various pressures. MXene and CB greatly increase the electrical conductivity and measurement range of the piezoresistive sensors. The existence of microcracks allows the sensor to sensitively capture micropressure signals, such as human radial artery pulse and respiration. In addition, the large-area conductive framework permits the sensor to maintain high responsiveness over a huge strain range and to distinguish various degrees of human movement. Furthermore, the sensor has shown excellent performance in controlling smart devices through external pressure as a human–machine interface. The pressure sensor based on LbL self-assembled MXene/CB on a PU sponge has potential applications in motion signal detection, artificial intelligence, and other fields.