ELECTROROTATION BEHAVIOR OF AGGREGATED PARTICLES - A THEORETICAL-STUDY

Electrorotation provides a convenient method for measuring the polarizability of single particles in suspensions as a function of the frequency of an applied rotating electric field. A theoretical description is given of the electrorotation behavior of a dielectric particle with an interior consisting of a large number of smaller particles. This hypothetical ''aggregate'' particle consist of a three-dimensional array of cubes separated by a uniform gap. The particle contains many smaller particles or vesicles, and since each vesicle represents a polarizable element we are able to describe the electric properties of the interior by averaging the dielectric behavior of the individual elements. Using this assumption we obtained the dielectric constant and the conductivity of the interior of the particle as frequency-dependent parameters. The intensity of aggregation was expressed by the dielectric parameters in the gap between the particles. The theoretical model was used to interpret the behavior of an exocytotic cell, an aggregate of cells and an aggregate of droplets (either water in oil or oil in water).