Solubilization of <i>n</i>-decane into <i>n</i>-decyl-polyoxyethylene surfactants: A cavity forming free energy based model

Abstract

The present paper reports the results of a theoretical study of the forces and factors driving the solubilization of <i>n</i>-alkane solubilizates into the micellar core of some non-ionic surfactants, based on a micellar model which· includes the cavity forming free energy as a component of micellization. The solubiIizate is <i>n</i>-decane and the non-ionic surfactants considered are <i>n</i>-decyl-polyoxyethylene surfactants. The extent of solubilization, i.e. the mole fraction of the solubilizate within the core has been calculated. The results indicate that the incorporated solubilizate has more translational and rotational degrees of freedom as compared to those of the tail parts of the surfactants present in the core. This drives the total free energy of aggregation after solubilization into a more favourable direction. The results are in fair agreement with the experimental results.