Why Measure Thermodynamic Properties of Micellar Systems?

Micellar systems are often very complex, involving many species and microphases which are in dynamic equilibrium. In this respect, the usefulness of theimodynamic properties is often questioned since they are bulk properties which are averaged over species, space and time, and it is only through models that information on structure can be deduced. However, such properties can be measured precisely, are very sensitive lo phase changes and lend themselves readily to mathematical modelling. Therefore, provided their limitations are well recognized, they can be excellent complementary tools for the understanding of colloidal systems. The advantages and limitations of thermodynamic properties and models for the study of micellar systems are illustrated with surfactant solutions, ternary micellar systems, and microemulsions.