title: Dielectrophoresis of charged colloidal suspensions.
abstract: We present a theoretical study of dielectrophoretic (DEP) crossover spectrum of two polarizable particles under the action of a nonuniform ac electric field. For two approaching particles, the mutual polarization interaction yields a change in their respective dipole moments, and hence, in the DEP crossover spectrum. The induced polarization effects are captured by the multiple image method. Using spectral representation theory, an analytic expression for the DEP force is derived. We find that the mutual polarization effects can change the crossover frequency at which the DEP force changes sign. The results are found to be in agreement with recent experimental observation and as they go beyond the standard theory, they help to clarify the important question of the underlying polarization mechanisms.
authors.affiliation: Biophysics and Statistical Mechanics Group, Laboratory of Computational Engineering, Helsinki University of Technology, P.O. Box 9203, FIN-02015 HUT, Finland.
authors.forename: J P
authors.initials: JP
authors.lastname: Huang
authors.forename: Mikko
authors.initials: M
authors.lastname: Karttunen
authors.forename: K W
authors.initials: KW
authors.lastname: Yu
authors.forename: L
authors.initials: L
authors.lastname: Dong