Electrophoresis of a spherical particle along the axis of a cylindrical pore: Effect of electroosmotic flow
Journal
Journal of Colloid and Interface Science
Journal Volume
276
Journal Issue
1
Pages
248-254
Date Issued
2004
Author(s)
Abstract
The electrophoresis of a spherical particle along the axis of a cylindrical pore is investigated under conditions of low surface potential and thick double layer. In particular, the effect of electroosmotic flow is taken into account. The results of numerical simulation reveal that if both particle and pore are positively charged, the variation of the mobility of a particle may have a local minimum as the thickness of the double layer varies, which is not reported in the literature. This is mainly due to the charge induced on the particle surface, which arises from the presence of the charged boundary. Depending upon the level of the surface potential of the pore, the presence of the local minima may lead to a reversal in the direction of particle movement as the thickness of the double layer surrounding it varies: if the surface potential is either too low or too high, reversal does not occur; if it has a medium level, reversal occurs twice. This interesting observation can play a role in electrophoresis measurements. Previous analysis predicts that reversal always occurs once, regardless of the level of the surface potential of the pore. ? 2004 Elsevier Inc. All rights reserved.
Subjects
Boundary effect
Electroosmotic flow
Electrophoresis
Sphere in cylindrical pore
Thick double layer
Type
journal article