EFFECT OF THE SOLVENT COMPOSITION ON THE ELECTROPHORETIC COEFFICIENT OF POLYMER MODEL COLLOIDS

An experimental investigation on electrophoresis of polystyrene beads in methanol-water and ethanol-water is described. The electrophoretic transport is considered from the point of view of Thermodynamics of Ir reversible Processes. The electrophoretic phenomenological coefficient of model polymer colloids in both binary liquid mixtures has been mea sured. The influence of the composition of the mixture on the electrop horetic coefficient has been discussed on the basis of the variation o f zeta-potential, viscosity, dielectric permittivity and density with the molar fraction of alcohol in binary mixtures, The concentration de pendence of the electrophoretic coefficient is found to be non-linear in both cases studied. The zeta-potential has been shown to play a sig nificant role in the internal structure of the electrophoretic coeffic ient (l(21)) for the polystyrene/water-ethanol system only.