Effect of non-electrolyte additives on micellization and clouding behavior of silicone surfactant in aqueous solutions

In this paper the effects of 26 non electrolyte additives (including 12 alcohols, 7 glycols and 7 amides) on the association and clouding behavior of silicone surfactants (SS) in aqueous solutions have been studied. The results show that the addition of the polar organic liquid additives which are miscible with water increases the critical micelle concentrations (CMC) and cloud point of the SS, whereas the addition of the polar organic liquid additives which are partially soluble in water decreases the CMC and cloud point of SS. The change in Gibbs free energy of micellization in the presence of additives was obtained from the data on critical micelle concentrations. The influence of given additive on the micellization of SS was monitored from the changes in the free energy of micellization values for the surfactant solutions in water and water + additives. For additives belonging to a particular homologous series the effect on the cloud point and micellization is correlated to the length of the hydrophobic alkyl chain.