THEORETICAL STUDIES ON ELASTICITY OF MICROEMULSIONS

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Microemulsions, vesicles and cell membranes have self-assembling wall structures made of surfactant molecules. The understanding of their elastic properties is particularly important for the understanding of some life processes and pathological diseases on the microscopic level. However, the elastic property is far from being completely understood in a fundamental way. Among these systems, microemulsions are the simplest in structure, and therefore, are ideal for research. The elastic information about microemulsions will have profound implications for characterizing animate cell structures. The elastic property of microemulsions can be inferred through the measurements of their Electro-Optical Bifringence. The Kerr coefficients of the optical bifringence of the (water/AOT/oil) system have been extensively measured at Fayetteville State University. The experimental data show a phi2 - scaling behavior. No existing theory could properly explain these data collectively. It appears that a relevant theory will have to incorporate many-droplet correlation in presence of an electric field. We will: (1) use a dimer model to fit the experimental data and explore the origin of high alignment; (2) reconsider the data based on the structure of multiple-droplet clusters; (3) use the statistical theory of depletion force and Monte Carlo simulation to explore cluster formation in microemulsions. The principal investigator will closely collaborate with Dr. Matthew Edwards, the former experimentalist in the same subproject, at Spelman College, receive further experimental data from him and make suggestions to him for future experiments. For this subproject, pertaining to elasticity of microemulsions, the student trainees will be involved in all aspects of the research activities, including computer programming, and fitting the data. They will also help to prepare and present the results in papers and talks.