Viscosity and Structural Relaxation in Suspensions of Hard-Sphere Colloids

Abstract

Viscometry and dynamic light scattering (DLS) were used to study suspensions of colloidal particles which interact like hard spheres. The rate of ``structural relaxation'' of microscopic density fluctuations, indicated by the long-time diffusion coefficient measured by DLS at the peak of the static structure factor, was found to vary with particle concentration quantitatively like the inverse of the low-shear-rate viscosity. Sample concentrations were calibrated with respect to the thermodynamic ``freezing'' transition of the suspension.