Brownian dynamics simulations of self-diffusion and shear viscosity of near-hard-sphere colloids.

Abstract

We use Brownian dynamics simulations to calculate the long-time self-diffusion coefficients and Newtonian viscosities of model near-hard-sphere colloidal liquids without hydrodynamic interactions using a continuous potential: (a) an ${\mathit{r}}^{\mathrm{\ensuremath{-}}\mathit{n}}$ interaction between the model colloidal particles, with exponents n varying between 6 and 72, and (b) a Yukawa potential. We show that the diffusion coefficients increase and the viscosity decreases as the interaction potential becomes softer. The time-dependent self-diffusion coefficients and shear-stress correlation functions can be represented by a fractional exponential form at all volume fractions up to 0.5.