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Electrophoretic motion of ideally polarizable particles in a microchannel
Author(s) -
Wu Zhemin,
Gao Yandong,
Li Dongqing
Publication year - 2009
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200800381
Subject(s) - microchannel , polarizability , electric field , particle (ecology) , vortex , electrophoresis , mechanics , molecular physics , materials science , dielectrophoresis , magnetosphere particle motion , physics , classical mechanics , atomic physics , chemistry , quantum mechanics , magnetic field , oceanography , chromatography , molecule , geology
The induced‐charge electrophoretic (ICEP) motion of ideally polarizable particles in a microchannel is numerically studied in this paper. A complete 3‐D multi‐physics model is set up to simulate the transient ICEP motion of spherical ideally polarizable particles in a microchannel. The study shows that a non‐uniform distribution of induced surface charge occurs when an ideally polarizable particle is immersed in an externally applied electric field, resulting in a varying slipping (EOF) velocity along the particle's surface and hence producing micro vortexes in the liquid. The numerical results verify that the steady‐state ICEP velocity of an ideally polarizable particle does not differ from the electrophoretic velocity of a non‐conducting particle, although the flow field near the particle does. A strong wall‐repelling effect of ICEP is found when the polarizable particle is placed close to the channel wall. This is due to the lifting effect generated from the interaction between the induced micro vortexes and the channel wall and depends on the electric field and the particle size. The wall effects on ICEP motion can be used for focusing particles and for separation of particle by density.