A Self-Powered Piezoelectric Nanofibrous Membrane as Wearable Tactile Sensor for Human Body Motion Monitoring and Recognition

Wearable sensors have drawn vast interest for their convenience to be worn on body to monitor and track body movements or exercise activities in real time. However, wearable electronics rely on powering systems to function. Herein, a self-powered, porous, flexible, hydrophobic and breathable nanofibrous membrane based on electrospun polyvinylidene fluoride (PVDF) nanofiber has been developed as a tactile sensor with low-cost and simple fabrication for human body motion detection and recognition. Specifically, effects of multi-walled carbon nanotubes (CNT) and barium titanate (BTO) as additives to the fiber morphology as well as mechanical and dielectric properties of the piezoelectric nanofiber membrane were investigated. The fabricated BTO@PVDF piezoelectric nanogenerator (PENG) exhibits the high β-phase content and best overall electrical performances, thus selected for the flexible sensing device assembly. Meanwhile, the nanofibrous membrane demonstrated robust tactile sensing performance that the device exhibits durability over 12,000 loading test cycles, holds a fast response time of 82.7 ms, responds to a wide pressure range of 0-5 bar and shows a high relative sensitivity, especially in the small force range of 11.6 V/bar upon pressure applied perpendicular to the surface. Furthermore, when attached on human body, its unique fibrous and flexible structure offers the tactile sensor to present as a health care monitor in a self-powered manner by translating motions of different movements to electrical signals with various patterns or sequences.The online version contains supplementary material available at 10.1007/s42765-023-00282-8.