HYDRODYNAMIC INTERACTIONS IN CONCENTRATED SUSPENSIONS

We study the effects of hydrodynamic interactions on the diffusion of hard spheres in concentrated suspensions. Using a multiple-light-scattering technique that measures the early-time behavior, we find Deff/D0=1-(1.86±0.07), where is the volume fraction of spheres, Deff is the effective diffusion coefficient, and D0 is the free-particle diffusion coefficient. This agrees with the linear term calculated theoretically for short-time self-diffusion. The short-time diffusion coefficient is also found to be continuous across the freezing transition. © 1990 The American Physical Society.