Simultaneous Measurement of Viscoelasticity and Electrical Conductivity of an Electrorheological Fluid

Simultaneous measurements of viscoelasticity and electrical conductivity are performed to study the dynamic characteristics of structures formed in a highly concentrated electrorheological suspension under a dc electric field of 1.8 kV/mm. Small amplitude oscillatory shear measurements reveal that there is no direct correlationbetween theelasticmodulusand theelectrical conductivity of the suspension. Asignificant increase in conductivity is observed following large amplitude oscillatory shear and, in this case, the linear elasticmodulus is also substantially enhanced. These observations are interpretedaccording to the concept of contact disorder arising from the anisotropic shape of the particulate phase.