Electrically Conductive AgNPs/TPU-Electrospun Fibers with Hierarchical Microstructures by a One-Step Method for a High-Performance Flexible Pressure Sensor

To obtain flexible pressure sensors with simple preparation process, high sensitivity, fast response time, wide detection range, and good stability at the same time is still a great challenge. Herein, silver trifluoroacetate (C2AgF3O2) was introduced into thermoplastic polyurethane (TPU)-electrospun solution, and a C2AgF3O2/TPU nanofiber film with hierarchical microstructure was prepared by “one-step” electrostatic spinning. Then, the conductive silver nanoparticle/TPU composite nanofiber film was obtained after the reduction of the C2AgF3O2/TPU nanofiber film. The hierarchical microstructure of the nanofiber film consists of tiny bumps with varying heights on the surface and holes with different sizes inside, which achieves a wide detection range of 0–100 kPa and a high sensitivity of 7.51 kPa–1. In addition, the response time and recovery time are 100 and 70 ms, respectively, and the stability of the sensor is still high even after 1000 test cycles of testing. The developed sensors show good sensing performance in the monitoring of pulse, finger movement, Morse code, and other signals, proving that they have a broad application prospect in human motion detection and wearable devices.