Flexible Piezoresistive Pressure Sensor Based on Electrospun Rough Polyurethane Nanofibers Film for Human Motion Monitoring

Flexible piezoresistive pressure sensors have been attracted a lot of attention due to their simple mechanism, easy fabrication, and convenient signal acquisition and analysis. Herein, a new flexible piezoresistive sensor based on microstructured electrospun rough polyurethane (PU) nanofibers film is assembled. The microstructured PU film with tiny bumps is prepared in one step via electrospinning technology, which imparts a microstructured rough upper surface and a smooth lower surface. With this unique microstructure, we have made it possible for PU/Ag films to serve as sensing layers for piezoresistive sensors by introducing a silver conductive layer on the surface of electrospun PU film. The fabricated piezoresistive pressure sensor delivers high sensitivity (10.53 kPa-1 in the range of 0-5 kPa and 0.97 kPa-1 in the range of 6-15 kPa), fast response time (60 ms), fast recovery time (30 ms), and long-time stability (over 10,000 cycles). This study presents a fabrication strategy to prepare the microstructured PU nanofiber film using electrospinning technology directly, and the as-developed sensor shows promise in applications such as wrist pulse measurement, finger movement monitoring, etc., proving its great potential for monitoring human activities.