Dielectric Polarization of Electrorheological Suspensions

The relation between electrorheological (ER) effect and dielectric properties of Polymer-based and inorganic-based suspensions were investigated. It is found that ER effect is determined not only by the dielectric constant of the suspended particles, but also by the dielectric loss, which provides a criterion whether suspension exhibits ER effect. The wagner model, which describes the interfacial polarization occurring in multiphase systems, was introduced to predict the dielectric behaviours of ER suspensions. A good agreement is found between experiments and theoretical predictions. The conductivity of the dispersed particles, the working temperature range and working frequency range of ER suspension can be optimized with Wagner model. The other ER phenomena such as the effect of water content were also explained by using this model.