sulation are predicted by equating appropriate chemical po-The solubilization of solutes in surfactant aggregates (micelles ) tentials to each other. This approach is quite useful, but is studied using lattice-based Monte Carlo simulations. Various requires independent information on chemical potentials. properties such as the size and shape of the micelles, the critical Analytical results are also possible through a combination micelle concentration, the locus of solubilization, and the partition of lattice models ( 17) and statistical thermodynamics under coefficient of the solute are obtained, and the implications of the sufficient simplifications ( 18,19) . However, this route is results for the thermodynamics of solubilization are examined.
too restrictive since one needs to fix quantities such as the
The presence of contaminants in the solution affects micellar propsize and the shape of the micelle. Related to the latter aperties by promoting micellization and stabilizing micelles. The ratio of head group size to tail group size for the surfactant is found proach are Ising-type models ( 20, 21 ) , which have been to greatly affect both micellar properties and contaminant solubiliused to study surfactant solutions and surfactant-oil -water zation. The partitioning of the solute is found to be independent systems. In such models the molecules are represented by of surfactant concentration, but increases with solute concentra-''spins'' on lattice sites and / or by near-neighbor bonds. As tion. The results show that contaminant partitioning is controlled a result, they are restricted in their ability to represent the primarily by enthalpic contributions.