title: Effects of structural properties of the Stern layer on the electrophoretic migration of a highly charged spherical macroion.
abstract: The electrophoretic migration of a highly charged spherical macroion suspended in an aqueous solution of NaCl is studied using the molecular dynamic method. The objective is to examine the effects of the colloidal surface charge density on the electrophoretic mobility (μ) of the spherical macroion. The bare charge and the size of the macroion are varied separately to induce changes in the colloidal surface charge density. Our results indicate that μ depends on colloidal surface charge density in a nonmonotonic manner, but that this relationship is independent of the way the surface charge density is varied. It is found that an increase in colloidal surface charge density may lead to the formation of new sublayers in the Stern layer. The μ profile is also found to have a local maximum for a bare charge at which a new sublayer is formed in the Stern layer, and a local minimum for a bare charge at which the outer sublayer becomes relatively dense. Finally, the electrophoretic flow caused by the migration of the spherical macroion is studied to find that one decisive factor causing the electrophoretic flow is the ability of the macroion to carry anions in the electrolyte solution.
authors.affiliation: Department of Mechanical Engineering, Isfahan University of technology, Isfahan, Iran.
authors.forename: Majid
authors.initials: M
authors.lastname: Rezaei
authors.affiliation: Department of Mechanical Engineering, Isfahan University of technology, Isfahan, Iran.
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Azimian
mesh_terms: D004586:Electrophoresis; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D055672:Static Electricity; D013499:Surface Properties
keywords: Electric double layer; Electrophoretic mobility; Molecular dynamics; Stern layer; Surface charge density