Induced dipoles and dielectrophoresis of nanocolloids in electrolytes

Abstract

Electric induced dipoles of nanocolloids the size of the Debye length are shown to be one order stronger than predicted by the classical Maxwell-Wagner theory and its extensions. The difference is attributed to normal ion migration within the diffuse layer, and adsorption onto the Stern layer at the poles. The characteristic relaxation frequency (the crossover frequency for dielectrophoresis) is shown to be inversely proportional to the $RC$ time of the diffuse layer capacitance and resistance, and has an anomalous $-1$ scaling with respect to the product of the Debye length and the particle size.