The surface charge density influence on the electrokinetic properties of model colloids: Solvent composition effect

This paper deals with two problems found in electrokinetics, the anomalous behavior exhibited by most polymer colloids and the discrepancy between the zeta potentials obtained from different electrokinetic phenomena. Electrop horetic mobility for dilute dispersions and streaming current for concentra ted dispersions are used to determine the zeta-potential. Two systems with different features (particle radius and surface charge density) have been s tudied. The influence of sigma(0) on the above-mentioned problems seems to be very important. In order to test this hypothesis, different nonaqueous m edia were used, which were significantly different in several liquid media properties (such as bulk conductivity, dielectric constant, and viscosity) and particle properties (such as surface charge density). (C) 1999 Academic Press.