ELECTROKINETIC PROPERTIES OF SURFACTANT-STABILIZED OIL DROPLETS

To study the electrokinetic behavior of highly charged colloidal parti cles, we used monodisperse oil drops suspended in water and stabilized with a surfactant, sodium dodecylsulfate. Results from dynamic light scattering, conductivity, and electrophoretic mobility measurements sh ow that the emulsion particles have high zeta-potentials, correspondin g to a large density of surfactant ions on the surface. Attempts to re concile results from mobility and conductivity measurements using the standard electrokinetic model were unsuccessful. The inadequacy of the standard model is ascribed to the high surface potential of the dropl ets and attendant changes in the counterion density and properties of the inner part of the diffuse layer.