THERMODYNAMICS OF MICROEMULSION FORMATION .1. ENTHALPY OF SOLUTION OF WATER IN BINARY (TRITON-X 100 + BUTANOL) AND TERNARY (HEPTANE + TRITON-X 100 + BUTANOL) MIXTURES AND HEAT-CAPACITY OF THE RESULTING SYSTEMS

The enthalpies of solution of water in binary mixtures of Triton X 100 (TX 100) and butanol and ternary mixtures of TX 100, butanol, and heptane as well as the heat capacities of the resulting ternary (TX 100, butanol, and water) and the quaternary (heptane, TX 100, butanol, and water) mixtures were measured. The enthalpy changes to form solvated mixed TX 100 and butanol and stable microemulsions, holding maximum water (expressed per mole of water addition), were essentially negative. The measured heat capacities were greater than the calculated heat capacities based on ideal mixing. The results indicated interactions among the components, leading to the formation of internally organized media, contributed by the deaggregation and solvation of the amphiphiles.