Nonlinear response analysis of a polymer-based piezoresistive flexible tactile sensor at low pressure

Flexible tactile sensors with superior sensitivity and linearity are in high demand for many applications, which require long-term and reliable detection. Low-pressure characterization is crucial in many applications. Surface microstructuring and compositional alterations have frequently been employed to improve the low-pressure performance of these sensors. In this letter, the nonlinear response of a polymer-based piezoresistive flexible tactile sensor is investigated by introducing changes in the mechanical properties of polydimethylsiloxane elastomer when altering the nature and thickness of the substrate. It is observed that there is significant nonlinearity in several sensor parameters within a low-pressure region of 0-1.5 kPa. When porosity is introduced, sensitivity rises by 27.7%. Furthermore, when the thickness is reduced in half, the sensitivity increases by 89.13%. When the applied pressure is increased, the overall sensitivity decreases by 83.7%. A similar trend is also seen in the resistive response output of the sensor, and the 2-mm thick-porous sensor, among others, has the lowest detection limit of 0.05 kPa.