Self-Healing Flexible Pressure Sensor for Human Motion Detection Based on Silver-Nanoparticle-Modified Polyimide Membranes

Polyimide (PI) nanofibers are highly suitable for applications in wearable electronic devices due to their excellent mechanical flexibility and good durability. Herein, a low-cost, self-healing flexible pressure sensor (PI@Ag) is demonstrated that is based on silver-nanoparticle-modified polyimide. Uniformly distributed Ag nanoparticles form a three-dimensional conductive network on the nanofiber, which imparts the flexible sensor with high sensitivity (197 kPa–1), wide response range (100 Pa–50 kPa), fast response time (400 ms), low operating voltage (0.02 V), and excellent durability (loading/unloading test of 2000 cycles under 10 kPa). Moreover, the self-healing encapsulating material can protect the inner sensing material when the surface of the sensor is damaged, thereby ensuring the integrity of the pressure sensor. The prepared PI@Ag sensors demonstrate the ability to monitor an entire range of motions when they are attached to human body. Furthermore, equipping the PI@Ag sensors with wireless Bluetooth connectivity enables users to transmit messages via Morse code. The PI@Ag sensors are expected to be widely used in motion monitoring, disease diagnosis, and human–machine interaction.