Influences of compression cycles on piezocapacitive effect of carbon black filled silicone rubber composite

The relation between the pressure and the capacitance of the carbon black filled silicone rubber composite with the carbon black content ranging from 5 vol.% to 9 vol.% (this content range can ensure the reinforcement effect and the flexibility of the composite for sensor development) under the multi compression cycles is researched. The capacitance of the composite increases with the increase of the pressure. There are deviations between the thicknesses/capacitivities of the composite under the same pressure in the different compression cycles, which results in the repeatability error of the piezocapacitivity of the composite. The experimental results show that the repeatability can be improved by increasing the number of the compression cycles. Therefore, the piezocapacitive effect of the composite has the potential to be used to measure the compressive pressure by applying the multi pre-compression cycles on the composite. The further analyses show that the hysteresis error, the nonlinear error and the sensitivity decrease with the increase of the number of the compression cycles.