Ion size effects on the electrokinetics of salt-free concentrated suspensions in ac fields

Abstract

We analyze the influence of finite ion size effects in the response of a salt-free concentrated suspension of spherical particles to an oscillating electric field. Salt-free suspensions are just composed of charged colloidal particles and the added counterions released by the particles to the solution, that counterbalance their surface charge. In the frequency domain, we study the dynamic electrophoretic mobility of the particles and the dielectric response of the suspension. We find that the Maxwell-Wagner-O'Konski process associated with the counterions condensation layer, is enhanced for moderate to high particle charges, yielding an increment of the mobility for such frequencies. We also find that the increment of the mobility grows with ion size and particle charge. All these facts show the importance of including ion size effects in any extension attempting to improve standard electrokinetic models.

J. Colloid Interface Sci., in press, 13 pages, 9 figures

References in corpus (5)

• Double layer in ionic liquids: Overscreening vs. crowding
• Nonlinear electrophoresis of dielectric and metal spheres in a nematic liquid crystal
• Electric double layer for spherical particles in salt-free concentrated suspensions including ion size effects
• DC electrokinetics for spherical particles in salt-free concentrated suspensions including ion size effects
• Diffusion and conduction in a salt-free colloidal suspension via molecular dynamics simulations

Cited by in corpus (3)

• Computer Simulations of Charged Colloids in Alternating Electric Fields
• Electric double layer of colloidal particles in salt-free concentrated suspensions including non-uniform size effects and orientational ordering of water dipoles
• Computer simulations of single particles in external electric fields