Diffusion and structure in dense binary suspensions

Abstract

Model colloids composed of two widely separated sizes of poly- styrene spheres are studied at high volume fractions using an optical, multiple-scattering technique. These measurements probe hydrodynamic forces between unlike particles, as well as static, structural predictions made using the Percus-Yevick approximation. The dynamic data corroborate currently available hydrodynamic theories on very short length scales; the dynamic data also reveal a new, experimentally accessible range of intermediate length scales which currently available theories cannot explain.