Electrophoresis of solid particles at large Peclet numbers

Document Type

Article

Publication Date

1-1-2002

Abstract

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 ID 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.

Identifier

0036023085 (Scopus)

Publication Title

Electrophoresis

External Full Text Location

https://doi.org/10.1002/1522-2683(200207)23:13<2012::AID-ELPS2012>3.0.CO;2-Y

ISSN

01730835

PubMed ID

12210253

First Page

2012

Last Page

2022

Issue

13

Volume

23

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