ity on ER activity under an oscillatory electric field. Ander-The dc conductive properties of oxidized polyacrylonitrile-based son (16) investigated how the finite conductivity of the diselectrorheological (ER) fluid under zero and oscillatory mechanipersed particles and the dispersed oil influenced polarization cal fields are examined. In a zero mechanical field, the resulting of the particles and field distortion. A conductivity model dc current through the ER fluid decreases approximately exponenwas presented by Felici et al. (17) to understand ER phetially with time to a limited value once the applied electric field nomena and ER mechanism. Thus the relationship between strength exceeds a critical value, whereas in an oscillatory mechan-ER activity and the conductivity of the dispersed material ical field, the dc current, obtained below the critical electric field, has been emphasized; however, the conductive property of changes with the applied mechanical frequency and strain ampli-ER fluid itself has been little stressed. Additionally, current tude. The conductance results measured under the off-state mechanical field are in accord with the quasi-one-dimensional vari-density of ER fluid is a very important specification in practiable range hopping model of charge carriers localized along a onecal uses, and a better understanding of the conductivity in dimensional chain. A modified fibrillated chain structure model is ER fluids is important and much needed. The present work presented to interpret the conductive behavior. The conductivity therefore utilized a dc electric field to examine conductive of this ER suspension is thought to depend on the number and behaviors of oxidized polyacrylonitrile-based ER suspennature of the continuous and the isolated conductive chains accusions when on-and off-state oscillatory mechanical fields mulated by the dispersed particles. A percolation theory is introwere applied. Two conductivity models, charging energy duced to analyze our results.