One 3D aerogel wearable pressure sensor with ultrahigh sensitivity, wide working range, low detection limit for voice recognition and physiological signal monitoring

With the rapid development of intelligent electronic devices, there is a growing demand for wearable pressure sensors with ultrahigh sensitivity, a wide working range, and a low detection limit simultaneously. In this paper, we create a piezoresistive pressure sensor with an ultralight (29.5 mg cm(-3)) and elastic three-dimensional (3D) chitosan/MXene (CS/MXene) composite aerogel. Because of the strong electrostatic attraction between CS and MXene, CS/MXene aerogels with good mechanical properties can be obtained in a single freeze-drying step with no additional chemical treatment. Furthermore, the abundant amino and carboxyl groups in CS form hydrogen bonds with the -O and -F groups on the surface of MXene, significantly improving the mechanical strength of the composite aerogel. As a result, the CS/MXene composite aerogel sensor has a sensitivity of 709.38 kPa(-1) in small pressure region (< 1 kPa) and 252.37 kPa(-1) in large pressure region (1-20 kPa), which are the highest values reported among the same type of aerogel sensors in the same pressure ranges. Furthermore, the sensor has a fast response time (120 ms), an ultralow detection limit of 1.4 Pa, and good stability (10,000 cycles with almost no fatigue). Because of the improved sensitivity, the competitive aerogel sensor can be used in a voice recognition system that can distinguish between different audio components. It also shows promise in detecting human and animal physiological signals ranging from low to high pressure and mapping spatial pressure distributions.