Dynamics of interacting Brownian particles in concentrated colloidal suspensions.

We are concerned with dynamic properties of interacting Brownian particles in concentrated colloidal suspensions. An effective diffusion coefficient measured by the modulated in phase low-coherence dynamic light scattering technique is investigated as a function of the volume fraction. The experimental results are compared with the numerical ones calculated under both the Cohen-de Schepper approximation for hydrodynamic interaction and the Percus-Yevick approximations for structural effect. It is confirmed that the Brownian motion of particles in the range of volume fraction from 0.01 to 0.2 is mainly dominated by the hydrodynamic interaction rather than the structural effect, which can be described well by the Cohen-de Schepper approximation.