Relationship between electric current and matrix modulus in electrorheological elastomers

We have carried out a series of tests on electrorheological elastomers, which consist of semi-conducting solid particles dispersed in a low-conductivity silicone-based elastomer, with the investigations focussing on the dependence of the DC electric current on the elastomer modulus. We find that when other conditions are held constant, the electric current under a particular electric field shows a significant decrease when an elastomer of higher modulus is used. This behaviour is explained qualitatively using a simple model based on the mechanical equilibrium of two competing forces: the electrostatic attraction force between the two adjacent particles in the field direction, and the elastic squeezing force due to the elastomer between the particles which resists their approach.