INTERFACIAL BENDING EFFECTS AND INTERFACIAL TENSIONS IN MICROEMULSIONS

ABSTRACT

Interfacial tensions and bending properties are calculated for surfactant films of drops in a microemulsion. When an excess phase of the drop material is present, the radius of the drops is typically less than the “natural” radius of curvature of the film owing to the system's tendency to maximize the number of drops and hence the entropy of drop dispersion. As a result, the drop films are found to have an appreciable bending stress as well as interfacial tensions differing significantly from that between the microemulsion and excess phase. Indeed, when the surfactant films are rather flexible and drop volume fraction in the microemulsion appreciable, calculated tensions with the excess phase can be ultralow even when drop tensions are not.