The role of hydrodynamic interactions in colloidal electrolyte friction and sedimentation

Based on a recently formulated mode coupling scheme for Brownian systems, n em analytical expressions are derived for the time-resolved tracer-diffusio n, electrolyte friction coefficient and sedimentation velocity of a colloid al macroion suspended in a many-component electrolyte solution. Use of thes e expressions yields good agreement with experimental data and Booth's theo ry of macroion sedimentation. Our theoretical expressions allow for a separ ate assessment of the influence of hydrodynamic and potential forces on the relaxation of the electrolyte atmosphere. Inclusion of hydrodynamic intera ctions (HI) effects is shown to be essential for a proper description of co lloidal electrolyte friction and sedimentation.