Concentration-polarization electrophoresis of charged colloidal dimers: A numerical study.

Flores-Mena, Jose Eladio; García-Sánchez, Pablo; Ramos, Antonio · Phys Rev E · 2025

basic_science · Level V

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Abstract

We present a numerical analysis of the translational motion of dimers composed of charged dielectric particles immersed in aqueous electrolytes under ac electric fields. The dimers consist of two spheres with different radii and are studied in two distinct configurations: (i) spheres connected by a negligibly thin wire, and (ii) spheres joined by a narrow neck. We explain their net motion as a consequence of steady electro-osmotic flows generated on the particle surfaces, a phenomenon known as concentration-polarization electrophoresis. Our numerical results are compared with recent experimental observations, and we discuss the similarities and discrepancies between the two.