The role of hydrodynamic interactions in colloidal electrolyte friction and sedimentation

Based on a recently formulated mode coupling scheme for Brownian systems, new analytical expressions are derived for the time-resolved tracer-diffusion, electrolyte friction coefficient and sedimentation velocity of a colloidal macroion suspended in a many-component electrolyte solution. Use of these expressions yields good agreement with experimental data and Booth's theory of macroion sedimentation. Our theoretical expressions allow for a separate assessment of the influence of hydrodynamic and potential forces on the relaxation of the electrolyte atmosphere. Inclusion of hydrodynamic interactions (HI) effects is shown to be essential for a proper description of colloidal electrolyte friction and sedimentation.