Performance Enhancement of Flexible and Self-Powered PVDF-ZnO Based Tactile Sensors

Flexible, self-powered, and intelligent tactile sensors are essential for accurate sensing in prosthetic devices. This paper explores piezoelectric polyvinylidene difluoride - zinc oxide (PVDF-ZnO) nanocomposite layer-based sandwich assembly as tactile sensor. ZnO nanoparticle addition as filler can overcome the challenges associated with PVDF-based tactile sensors. The effect of filler particle size on the enhancement of sensing performance of PVDF-ZnO-based tactile sensors is investigated. Structural, morphological, piezoelectric and thermal studies were performed on the PVDF-ZnO composite layers using SEM, EDS, DC-EFM and Raman Spectroscopy. A comparative investigation of the potential developed across the sensor samples with different filler particle sizes was performed for touch and bending actions. The obtained results showed a remarkable improvement in performance due to particle size reduction of the ZnO fillers. The nanocomposite sensor with less filler particle size generated more voltage on the same applied force. The experimental analysis demonstrates that the filler size reduction can improve the piezo-voltage response up to 123 mV/N for dynamic touch events. The self-powered sensor also has excellent potential in detecting finger bending action with a response of 29 mv/degrees. The results demonstrate the promising application of the polymer nanocomposite-based sensor in the prosthetic application.