This award supports Professor Clarence A. Miller of Rice University to collaborate with Professor Heinz Hoffmann of the Physical Chemistry Department of the University of Bayreuth, Germany. They will carry out joint research on equilibrium and dynamic properties of surfactant systems that will build on and enhance their ongoing independent work on surfactant dynamics.. The two laboratories will share the work of determining equilibrium phase behavior of systems containing a particular zwitterionic surfactant in pure form plus various hydrocarbons and straight-chain alcohols. Then each laboratory will conduct experiments suited to its specialized equipment to elucidate other behavior in systems containing the same zwitterionic surfactant under different chemical and physical conditions. Dr. Miller's laboratory will use videomicroscopy to investigate the dynamic behavior that occurs when surfactant solutions contact oil. Dr. Hoffmann's laboratory in Germany will measure rheological, electric birefringence and other dynamic response properties of pure phases for a number of systems. Such techniques have never been applied to the L3 phase. Comparing the results with theoretical models is sure to advance fundamental understanding of the microstructure of this phase. The general objective of this joint work is to obtain a better understanding of certain phases in surfactant systems, especially the so-called L3 phase, an isotropic liquid phase which occurs in a variety of surfactant systems under conditions quite different from those where ordinary micellar solutions are found. The collaborators will also examine the lamellar liquid crystalline phase, which exists over a wide range of water content and presumably has a wide range of rheological behavior. Relating the morphology of this phase to the data on physical properties from the German measurements should provide a better understanding of the manner in which new phases, such as the lamellar liquid crystal, form at the initial interface between aqueous surfactant solutions and oil. Such knowledge will have a variety of practical applications.
