Electrophoresis of concentrated colloidal dispersions in low-polar solvents

Teun Vissers; Arnout Imhof; Félix Carrique; Ángel V Delgado; Alfons van Blaaderen

doi:10.1016/j.jcis.2011.04.113

Electrophoresis of concentrated colloidal dispersions in low-polar solvents

J Colloid Interface Sci. 2011 Sep 15;361(2):443-55. doi: 10.1016/j.jcis.2011.04.113. Epub 2011 May 11.

Authors

Teun Vissers¹, Arnout Imhof, Félix Carrique, Ángel V Delgado, Alfons van Blaaderen

Affiliation

¹ Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands. t.vissers@uu.nl

PMID: 21700292
DOI: 10.1016/j.jcis.2011.04.113

Abstract

We present a method to accurately measure the electrophoretic mobility of spherical colloids at high volume fractions in real space using confocal laser scanning microscopy (CLSM) and particle tracking. We show that for polymethylmethacrylate (PMMA) particles in a low-polar, density- and refractive-index-matched mixture of cyclohexylbromide and cis-decahydronaphthalene, the electrophoretic mobility decreases nonlinearly with increasing volume fraction. From the electrophoretic mobilities, we calculate the ζ-potential and the particle charge with and without correcting for volume fraction effects. For both cases, we find a decreasing particle charge as a function of volume fraction. This is in accordance with the fact that the charges originate from chemical equilibria that represent so-called weak association and/or dissociation reactions. Finally, as our methodology also provides data on particle self-diffusion in the presence of an electric field, we also analyze the diffusion at different volume fractions and identify a nonlinear decreasing trend for increasing volume fraction.