THE TEMPERATURE-DEPENDENCE OF THE ELECTRICAL-PROPERTIES AND STRENGTH OF ELECTRORHEOLOGICAL FLUIDS

Electrical and rheological properties were determined at 25-160-degrees-C for an electrorheological fluid consisting of 20 vol % zeolite particles (containing 8 wt % water) in silicone oil. A model is proposed which explains the mechanical response in terms of the dielectric mismatch between the particles and the carrier fluid and a local concentration of the electric field. Thermal activation analysis of the data suggests that the temperature dependence of the electrical conductivity of the fluid reflects the diffusion of the Na+ ions in the zeolite particles. It is not clear whether the temperature dependence of the shear stress and the dielectric constant of the particles represents an equilibrium or kinetic process.