BROWNIAN DYNAMICS SIMULATIONS OF MODEL NEAR-HARD-SPHERE SUSPENSIONS

Brownian dynamics simulations of near-hard sphere (r-24 potential part icles) have been carried out for model colloidal systems using a free- draining model for the hydrodynamic interactions. The phase volume of solids considered is in excess of 50%. We investigated the N-dependenc e of the shear thinning curves and found that the rheology of N = 108 and N = 256 systems were statistically indistinguishable. We demonstra ted that the shear induced ordering of the particles does not develop until the extent of shear thinning is nearly complete (i.e., as the se cond newtonian plateau is approached) We also report the effects of sh ear flow on the cartesian components of the pressure tensor and the lo ng-time self-diffusion coefficients. This analysis suggests that all t he thermodynamic and transport properties lose the x, y and z directio n degeneracy, present at equilibrium under the non-equilibrium conditi ons established at high shear rates.