Impedance characteristics of surface pressure-sensitive carbon black/silicone rubber composites

The surface pressure-sensitive characteristics of carbon black/silicon rubber (CB/SR) composites with positive pressure coefficient of impedance (PPCI) effect were researched. The linearity is very good when the impedance's logarithm changes with the applied load at optimal operating frequency (1 KHz). The pressure sensor based on the flexible composites exhibit fast response when pressures are applied and canceled with a response time of 3 s. The sensor appears a higher sensitivity in AC electrical field than that in DC electrical field. Dielectric polarization theory was used to explain the sensitive behavior of the pressure sensor. Internal structure diagrams of CB/SR composites were used to explain the positive pressure coefficient of resistive (PPCR) effect and negative pressure coefficient of capacitive (NPCC) effect. AC electric field is applicable for the flexible pressure sensor based on conductive silicon rubber composites.