Microscopic model for microemulsions. I. Ground state properties

The ground state of several variants of a new microemulsion model is examined in detail. We find oil–microemulsion–water and oil–surfactant–water equilibria, and coexistence between microemulsions of different geometrical structures (lamellar, tubular, and ‘‘brick’’). We find vanishing or low surface tension between bulk oil and water at the three-phase coexistence in different versions of the model. Our results suggest that the model is capable of reproducing many of the striking features of real microemulsions and deserves a detailed study at nonzero temperatures.