William Gelbart is supported by a grant from the Theoretical and Computational Chemistry Program to continue his work in statistical mechanical treatment of amphiphiles. He is studying the self-organizing properties and phase transitions of amphiphiles in water as a function of concentration. Three areas of new study are identified: a) coupling between micellar size/shape and long range order in concentrated surfactant in water systems; b) structures and flow properties of solutions of flexible micelles; and c) statistical mechanics of almost ideal solids under stress. Gelbart is using a whole host of analytical methodologies including density functional theory, mean field approximation, renormalization group approaches, and spin- vector-like Hamiltonian approaches supplemented in a few cases with Monte Carlo and molecular dynamics simulations. %%% Amphiphiles are long chainlike molecules which have water soluble polar groups at one end and oily hydrocarbon groups at the other end. Amphiphiles find widespread use as surfactants and detergents. These molecules tend to aggregate together in solution and self-organize into layers or micelles which are enclosed surfaces having the polar groups on the outside, and the long chain oily portions on the inside. Amphiphiles have widespread industrial and commercial use. Gelbart's theoretical research will help us to better understand the physical chemistry of this important class of chemical compounds, and to design even better materials of this type.
