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Electrophoresis of solid particles at large Peclet numbers
Author(s) -
Mishchuk Nataliya A.,
Dukhin Stanislav S.
Publication year - 2002
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683(200207)23:13<2012::aid-elps2012>3.0.co;2-y
Subject(s) - péclet number , electric field , electrophoresis , dipole , surface charge , concentration polarization , chemistry , polarization (electrochemistry) , zeta potential , convection , diffusion , mechanics , analytical chemistry (journal) , chemical physics , thermodynamics , physics , materials science , chromatography , nanotechnology , nanoparticle , biochemistry , organic chemistry , quantum mechanics , membrane
A theory of concentration polarization of a thin electrical double layer (DL) on a spherical particle is developed for the regime of large Peclet numbers which is realized in strong electric fields. In this regime, the concentration field arising outside DL is estimated under influence of diffusion and convection. According to the theory developed, polarization of DL at large Peclet numbers causes a change in the Stern potential, the formation of a dipole moment and the long‐range potential. The diffuse layer deviates strongly from spherical symmetry and electroneutrality, and the screen of the surface charge is provided not only by the diffuse atmosphere but also by the charge induced in the convective‐diffusion layer. The effect of electric field on the induced charge gives rise to the additional electroosmotic slip, that was called “secondary electroosmosis”. Thus, a nonlinear additional term for the Smoluchowski formula of electrophoretic velocity is based on the changes of ζ‐potential and on the secondary electroosmotic slip. The comparison of theory with experimental results revealed considerable fitting.