CONVECTION IN MODERATELY HIGH CONCENTRATED COLLOIDAL SUSPENSIONS

Dielectric response of concentrated colloidal suspensions

The determination of the low-frequency ~typically 0–1 MHz! dielectric dispersion of colloidal suspensions may become an electrokinetic tool of wider use if the accuracy of experimental data can be improved and if trustable theories, available for a wide range of situations, are made available. In the present work, we focus on the latter aspect: Since the dielectric constant of the suspensions i...

Nonequilibrium effects on slow dynamics in concentrated colloidal suspensions.

Structure and dynamics studies of concentrated micrometer-sized colloidal suspensions.

We present an experimental study of the structural and dynamical properties of concentrated suspensions of different sized polystyrene microspheres dispersed in glycerol for volume fraction concentrations between 10% and 20%. The static structure, probed with ultrasmall-angle X-ray scattering, shows a behavior very similar to that of hard spheres. The equilibrium dynamics is probed with ultrasm...

Nonequilibrium structure and rheology of concentrated colloidal suspensions: Linear response

We propose a simple theory for the pair distribution function of a sheared colloidal suspension. The starting point is an exact equation for the stationary state pair distribution. We assume that in a shear flow the higher order distributions can be expressed through the pair distribution in the same way as in an equilibrium state. To get explicit results we use a simple decoupling approximatio...

Thermal convection in colloidal suspensions with negative separation ratio.

Thermal convection in colloidal suspensions of nanosized particles is investigated. Representative examples for such materials are ferrofluids, but since we do not imply any external magnetic field, the description applies to nonmagnetic suspensions as well. With the grain size being large on molecular length scales, the particle mobility is extremely small, allowing to disregard the concentrat...