Electrophoresis of a Concentrated Dispersion of Nonrigid Particles

Abstract

Electrophoresis is one of the most important analytical tools for the quantification of charged entities in a dispersing medium. Although the electrophoresis of rigid entities has been studied extensively in the literature, corresponding analysis on nonrigid entities is relatively limited. The present study focuses on the electrophoresis of a concentrated dispersion of nonrigid particles for the case when the effect of double layer polarization may be significant. In particular, the effects of the surface potential of the particle, the volume fraction of the particles, the ratio (viscosity of the medium inside the particle/viscosity of the medium outside the particle), and the double layer thickness are discussed. Various phenomena specific to nonrigid entities that are not observed for the case of rigid entities are observed in this study, which include, for example, the fact that the variation of electrophoretic mobility as a function of double layer thickness exhibits an inflection point. We show that, under the same conditions, the electrophoretic mobility of a nonrigid particle is larger than that of a rigid particle, and this is pronounced if the double layer is thin.