Flexible Self-Powered Friction Piezoelectric Sensor Based on Structured PVDF-Based Composite Nanofiber Membranes

With the rapid development of the economy and technology, intelligent wearable devices have gradually entered public life. Flexible sensors, as the main component of wearable devices, have been widely concerned. However, traditional flexible sensors need an external power supply, lacking flexibility and sustainable power supply. In this study, structured poly(vinylidene fluoride) (PVDF)-based composite nanofiber membranes doped with different mass fractions of MXene and zinc oxide (ZnO) were prepared by electrospinning and were then assembled to flexible self-powered friction piezoelectric sensors. The addition of MXene and ZnO endowed PVDF nanofiber membranes with better piezoelectric properties. The structured PVDF/MXene-PVDF/ZnO (PM/PZ) nanofiber membranes with a double-layer structure, interpenetrating structure, or core–shell structure could further enhance the piezoelectric properties of PVDF-based nanofiber membranes through the synergistic effects of filler doping and structural design. In particular, the output voltage of the self-powered friction piezoelectric sensor made of a core–shell PM/PZ nanofiber membrane showed a good linear relationship with the applied pressure and could produce a good piezoelectric response to the bending deformation caused by human motion.