The stability of hydrophobic sols in the presence of surface active agents

Abstract

The zeta potential measurements were carried out in the presence of surface active agents under the conditions as described in Part I. The cell used in these measurements was similar to that described byMattson. The shape of zeta-potential-log10 concentration curves was found to be of S shaped. This behaviour was ascribed due to the strong adsorption of surface active agents at the solid-liquid interface. On the basis of these results changes in the charge density of the Gouy layer i.e. were calculated in the vicinity of the zero point of charge; these in turn led to computation of electro-chemical energy of adsorption. The magnitude of this energy varied from 5.730–6.160 cal per mole for different surface active agent used. An attempt has been made to give a physical picture of the mode of adsorption of these compounds on the surface of thorium dioxide particles.