Field-induced disturbance of the double layer electro-neutrality and non-linear electrophoresis

The influence of applied electric field on the field-induced variation of the electrolyte concentration (concentration polarization) disturbs the electro-neutrality of the system, represented by a dispersed particle and its electric double layer in electrolyte solution. The manifestation of this electro-neutrality disturbance in the non-linear electrophoresis was considered in the framework of a procedure of successive approximations in powers of the applied field strength. Analytic expressions describing the component of the electrophoretic velocity proportional to the cubic power of the applied field strength (cubic electrophoresis) were obtained for arbitrary values of the surface conductivity (of Dukhin number). The model restrictions are spherical non-conducting particle with homogeneous surface and thin double layer. (C) 2003 Elsevier Science B.V. All rights reserved.