ELECTRIC-FIELD-INDUCED PHASE-SEPARATION IN ELECTRORHEOLOGICAL FLUIDS

The phase separation into a high-density and a low-density phase, whic h occurs after a strong electric field is applied to an ER fluids, is demonstrated in terms of the Coulomb interaction energy of the system. The phase separation is manifested by two-dimensional pattern observe d in the field direction by means of a pair of transparent glass (TG) electrodes. The development of phase separation with an increasing fie ld is recorded by a computer image processing system consisting of a C CD video camera. The patterns are irregular and their characteristic s izes are determined by two-dimensional auto-correlation approach. The dependency of those patterns on external electric field is analyzed ba sed on statistical methods. Two critical fields are presented to chara cterize the electric-field-induced phase separation process in the ER fluid.