A LIGHT-SCATTERING STUDY OF THE NONLINEAR DYNAMICS OF ELECTRORHEOLOGICAL FLUIDS IN OSCILLATORY SHEAR

We report a real time, two-dimensional light-scattering study of the n onlinear dynamics of field-induced structures in an electrorheological (ER) fluid subjected to oscillatory shear. We have developed a simple kinetic chain model of the observed dynamics by considering the respo nse of a fragmenting/aggregating particle chain to the prevailing hydr odynamic and electrostatic forces. This theory of the dynamics is then used to describe the nonlinear theology of ER fluids, and it is concl uded that light scattering allows one to indirectly probe the stress i n an ER fluid. (C) 1995 Society of Rheology.