Volumetric study of mixed micelles of hexane-1,2-diol and some alkane-1,2,3-triols

Abstract

Aqueous solutions of mixtures of hexane-1,2-diol (HD) with octane-1,2,3-triol (OT) or nonane-1,2,3-triol (NT) have been studied. Densimetric measurements have been used to determine the critical micellar concentrations (c.m.c.s) of mixed micelles for various mole fractions. The apparent partial molar volumes, whose variation gave the volume change during the micellization of mixed micelles, where also determined. For the mixture HD–OT, mixed micelles, are formed over the whole range of mole fractions whereas for the HD–NT mixture, mixed micelles are formed only when the mole fraction of HD in the mixed solute is < 0.50.

The pseudo-phase separation model (psm) has been used to treat these mixed micelles and allows calculation of c.m.c.s as a function of the overall composition of the mixture and individual components. Explicit treatment of the monomer concentrations and micelle composition is also included.