Nonequilibrium structure of concentrated colloidal fluids under steady shear: leading-order response

The flow-induced microstructural distortions of dense colloidal dispersions under steady shearing are derived within a recent first-principles approach to the nonlinear rheology of colloidal fluids and glasses. The stationary structure factor is discussed to leading orders in shear rate gamma. We find that shear affects the stationary structure whenever the dressed Peclet/Weissenberg number Pe = gamma tau becomes appreciable; here tau is the structural or alpha-relaxation time. Close to vitrification, this predicts significantly larger shear distortions than expected from considering the bare Peclet number Pe(0); it compares gamma with the diffusion time of a colloid at infinite dilution.