A four component lattice model for nonaqueous microemulsions made with nonionic surfactants

A simple four component lattice model is used to reproduce qualitatively phase behavior of nonaqueous microemulsions. In microemulsions where glycerol and propylene glycol replace water, 2-3-2 phase transitions are observed as the glycerol content in the polar organic mixture increases. The model predicts such phase behavior and reproduces the effect of oil solvophobicity and the surfactant solvophilic-lipophilic balance. In addition, temperature insensitive phase behavior is observed in these nonaqueous mixtures and is predicted in the model. The results are used to propose possible molecular interaction mechanisms which would account for the microemulsion phase behavior. The model is compared with a similar model developed for water microemulsions and the differences are cast in light of the different molecular interactions which occur between propylene glycol, water, and nonionic surfactants.