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

Polyimide (PI) nanofibers are highly suitable for applicationsin wearable electronic devices due to their excellent mechanical flexibilityand good durability. Herein, a low-cost, self-healing flexible pressuresensor (PI@Ag) is demonstrated that is based on silver-nanoparticle-modifiedpolyimide. Uniformly distributed Ag nanoparticles form a three-dimensionalconductive network on the nanofiber, which imparts the flexible sensorwith high sensitivity (197 kPa(-1)), wide responserange (100 Pa-50 kPa), fast response time (400 ms), low operatingvoltage (0.02 V), and excellent durability (loading/unloading testof 2000 cycles under 10 kPa). Moreover, the self-healing encapsulatingmaterial can protect the inner sensing material when the surface ofthe sensor is damaged, thereby ensuring the integrity of the pressuresensor. The prepared PI@Ag sensors demonstrate the ability to monitoran entire range of motions when they are attached to human body. Furthermore,equipping the PI@Ag sensors with wireless Bluetooth connectivity enablesusers to transmit messages via Morse code. The PI@Ag sensors are expectedto be widely used in motion monitoring, disease diagnosis, and human-machineinteraction.