Sensitivity Analysis of ZnO NWs Based Soft Capacitive Pressure Sensors using Finite Element Modeling

Pressure sensors make an important component of electronic skin and its application in robotics, human-machine interfaces, and health monitoring. In this regard, soft capacitive sensors based on elastomeric dielectric materials and piezoelectric nanowires (NWs) have been shown to have good sensitivity, particularly in the low-pressure range of 0-10 kPa. In this work, we have simulated the capacitive sensors using finite element methods (FEM) to investigate the effect of piezoelectric properties of ZnO NWs incorporated into a polydimethylsiloxane (PDMS) dielectric material. Effect of NWs orientation and their dimensions on the sensitivity of the sensor have been studied. Simulations shows that with ZnO NWs in the PDMS matrix the sensors show higher sensitivity in low pressure range (0-10 kPa) than the bare PDMS based sensors. The estimated values and trends observed in this study were found to have good match with experimental results. Further, the simulation results show that the NWs aspect ratio could also influence the sensitivity of capacitive pressure sensors. The presented study shows the potential for using FEM for optimization of sensor design.