Frequency Dependence of Electroacoustic (Electrophoretic) Mobilities

Abstract

The direct characterization of electrokinetic mobilities in concentrated (>1 % (v/v)) dispersions is now feasible by using electrokinetic sonic amplitude (ESA) measurements of the acoustic pressure amplitude response to an applied radio frequency (rf) field. The calibration of such measurements in terms that can be related to static electrophoretic mobilities rests on the theoretical ratio of dynamic and static mobilities, |µ(ω)/µ(0)|, where ω is the angular frequency of the applied rf field. We report here dynamic and static electrophoretic measurements for colloidal polystyrene and poly(methyl methacrylate) latexes, alumina, and silica, and we examine the self-consistency of these measurem..