MXene Porous Nanocomposite Based Capacitive Pressure Sensor With High Performance for Human Motion Monitoring

Flexible capacitive pressure sensors (CPSs) have attracted valuable research attention, but there has been a critical challenge for them to simultaneously achieve high sensitivity, wide measurement range, and low cost. Herein, we propose an effective strategy to optimize the sensing performance of the CPSs by fabricating a porous dielectric nanocomposite with high permittivity and low compression modulus. It is innovative for a CPS to construct a dielectric by incorporating the highly conductive surface-silanized MXene (S-MXene) into the highly compressible thermoplastic polyurethane (TPU) porous frame to enhance its permittivity. We used a covalent surface modification method to modify MXene to improve its dispersion and interface adhesion with the matrix TPU. To construct the microporous skeleton, a facile and cost-effective coagulation method was carried out to create abundant porosity in the nanocomposite by non-solvent-induced phase separation. The CPS, assembled by sandwiching the porous dielectric nanocomposite in between two flexible electrodes, exhibits outstanding overall performance of a high sensitivity of 0.24 kPa−1 with a good linearity of 0.98 (<100 kPa), a wide detection range up to 500 kPa, a fast response time of 62 ms, and good functioning durability over 5000 cycles (~50 kPa). The prepared CPS demonstrates an extraordinary capability of real-time human motion monitoring, providing extensive insights into the application of wearable electronic devices, human–machine interfaces, and human healthcare treatment.