The Cataphoresis of Spherical Fluid Droplets in Electrolytes

Abstract

A theory of the electrophoresis of spherical fluid droplets in an electrolyte is developed. A general formula is given for the electrophoretic velocity in terms of the applied field, the potential distribution in and near the drops, and the dielectric constants and coefficients of viscosity of the liquid and electrolyte. It is assumed that the liquid drop retains its spherical form in cataphoresis and also that relaxation effects in the electrolyte may be neglected. Detailed formulas are worked out for the case of a Debye‐Hückel potential in the electrolyte, and the following charge distributions in the fluid sphere. (a) No charge within the sphere; the whole charge is concentrated on the interface. (b) Uniform volume distribution of charge. (c) Ionic double layer potential in the sphere. It is shown that sundry special cases of the theory agree with previous computations and that it is not legitimate to apply theories of the cataphoresis of solid particles to fluid drops.