Sedimentation velocity and potential in a concentrated suspension of charged liquid drops.

The sedimentation behavior of a concentrated suspension of charged liquid drops is analyzed theoretically at arbitrary surface potential and arbitrary double-layer thickness; that is, the effects of double-layer polarization and double-layer overlapping are taken into account. Kuwabara's unit cell model is employed to model the suspension system, and a pseudospectral method based on the Chebyshev polynomial is adopted to solve the governing electrokinetic equations numerically. Several interesting phenomena, which are of significant influence if the internal flow inside a liquid drop is taken into account, are observed.

Electrophoresis of a spherical dispersion of polyelectrolytes in a salt-free solution.

The electrophoretic behavior of a spherical dispersion of polyelectrolytes of arbitrary concentration is analyzed theoretically under a salt-free condition, that is, the liquid phase contains only counterions which come from the dissociation of the functional groups of polyelectrolytes. We show that, in general, the surface potential of a polyelectrolyte increases nonlinearly with its surface charge. A linear relation exists between them, however, when the latter is sufficiently small; and the more dilute the concentration of polyelectrolytes, the broader the range in which they are linearly correlated.

Electrophoresis of Carreau-drop dispersions with a charge-regulated surface.

The electrophoresis of a liquid-liquid dispersion, where the dispersed phase comprises drops of a shearing-thinning Carreau fluid with a charge-regulated surface and the dispersion medium is an aqueous electrolyte solution, is analyzed theoretically under the conditions of low surface potential, uniform weak applied electric field, and arbitrary double layer thickness. This is the first attempt for the description of the electrophoretic behavior of a dispersion containing non-Newtonian drops with a charge-regulated surface. We show that, in general, the more significant the shear-thinning nature of the drop fluid, the lower the concentration of drops, the lower the pH of bulk solution, or the higher the concentration of dissociable functional groups on drop surface, the larger the mobility.