The dielectric spectrum and the electrorheological effect in suspensions of varying conductivity: Part 1. Modeling of the dielectric spectrum

Abstract

The dielectric behavior of electrorheological (ER) suspensions composed of non-colloidal silica gel particles of irregular shape and liquids with varying conductivity is examined in this work. The dielectric properties of the suspensions are analyzed in the diluted and semi-concentrated regimes at different frequencies maintaining the electric field constant. Primarily, the dielectric behavior is studied with particular attention to the dependence of the dielectric relaxation process on particle concentration and their relation with the conductive behavior. The dielectric spectrum is analyzed with Maxwell–Wagner interfacial polarization model in the low frequency region and with the Debye model at moderate frequencies. A non-localized diffusion process (or ideal conduction) is considered to analyze the dielectric spectrum in more conductive suspensions. Since a strong correlation exists between the ER activity of a suspension and its dielectric spectrum, the modeling of the dielectric spectrum provides understanding of the polarization processes which induce the ER effect studied in Part 2.