VOLUMETRIC STUDY OF MIXED MICELLES OF HEXANE-1,2-DIOL AND SOME ALKANE-1,2,3-TRIOLS

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 concen trations (c.m.c.s) of mixed micelles for various mole fractions. The a pparent partial molar volumes, whose variation gave the volume change during the micellization of mixed micelles, were also determined. For the mixture HD-OT, mixed micelles are formed over the whole range of m ole fractions whereas for the HD-NT mixture, mixed micelles are formed only when the more fraction of HD in the mixed solute is <0.50.The ps eudo-phase separation model (psm) has been used to treat these mixed m icelles and allows calculation of c.m.c.s as a function of the overall composition of the mixture and individual components. Explicit treatm ent of the monomer concentrations and micelle composition is also incl uded.