Self-Diffusion of Interacting Colloids Far from Equilibrium

Forced Rayleigh scattering is used to measure the self-diffusion of charged polyball suspensions driven far from equilibrium by an oscillating shear flow. Aside from the usual enhancement of the diffusion due to Taylor dispersion, we observe an additional isotropic contribution which increases linearly with the shear rate. This anomalous contribution is absent in noninteracting samples and increases monotonically with the interparticle interaction strength.