Wed September 11th 2019
16:00 – 17:00
Seminar Dipolophoresis of ideally - polarizable cylindrical particle pairs
Itzchak Frankel


We study the dipolophoretic (DIP) motion resulting from the combined induced – charge electrophoretic (ICEP) and dielectrophoretic (DEP) interactions between a pair of identical, initially uncharged circular cylindrical particles suspended in an unbounded electrolyte solution and subject to a uniform external field acting in a plane perpendicular to the axes of the cylinders. Within the framework of the common thin – Debye – layer limit and sufficiently weak fields, we specifically focus on the cases of an AC field acting in a fixed direction in the plane and a rotating constant – magnitude field, respectively.
Both ICEP and DEP result in particles mutual attraction when their line – of – centres (LOC) is aligned with the external field and repulsion when it is perpendicular thereto. The nonlinearity inherent in both mechanisms gives rise to opposing effects acting to orient the LOC parallel to the external field (DEP) or perpendicular thereto (ICEP). Thus, at low frequencies, when the latter prevails, particles ultimately move apart in the direction perpendicular to the external field. With increasing frequency, DEP prevails over ICEP in a widening domain of the plane resulting in particles eventually pairing along field lines.
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The 10th Complex Motion in Fluids 2021
Max Planck Gesellschaft
Centre for Scientific Computing