Dielectrophoresis of Lossy Dielectrics

Dielectrophoresis of a solid particle in a liquid medium is usually studied under the assumption that the dielectrics are ideal. Real dielectrics, however, exhibit nonzero conductivities, and the results are sometimes unpredictable. The particular case of a lossy dielectric sphere in a lossy dielectric liquid is considered. The dielectrophoretic motion following the application of a dc field is studied, and it is shown that the motion is strongly affected by conductivities. From the results it can be deduced, for instance, that the separation of solid particles in liquid media can be based on differences of conductivities rather than differences of permitivities of the two media.