Personal Information and Interests

Education:
Ph.D., University of Wisconsin, 1981
M.Sc.Eng, University of Natal, Durban, South Africa, 1976
B.Sc.Eng, University of Natal, Durban, South Africa, 1972

Honors and Awards :
Founding Fellow, American Institute for Medical and Biological Engineering, 1992
Merck Faculty Development Award, 1989
Class of '22 Career Development Chair, 1988
Presidential Young Investigator Award, National Science Foundation, 1985
Everett Moore Baker Award for Excellence in Undergraduate Teaching, MIT, 1983

Academic Interests

Research Interests: transport phenomena, separation processes, microemulsions, colloids

Research Description

The thermodynamic and transport properties of organized molecular assemblies and colloidal suspensions can be important in a wide range of fields - synthesis of semiconductor particles, ceramics processing, biocatalysis in structured media, cell membrane transport, separations, food processing, tertiary oil recovery, drug delivery systems, cosmetics, phase transitions, etc. Our current focus is on understanding the physicochemical phenomena affecting these processes through analyses of the solute/polymer/micelle complexes backed up by a range of experimental probes, including spectroscopic analysis, and light, small-angle x-ray and neutron scattering. Also available are sophisticated experimental techniques for the measurement of fast dynamic processes, such as state-of-the-art iodine laser temperature jump and concentration jump methods. Typical projects in this area include the effects of curvature in microemulsions on interfacial solubilization and transport properties, the mechanisms of interfacial solubilization of proteins and other hydrophilic solutes by reversed micelles, the molecular reorganization process in microemulsion systems following temperature and concentration perturbations, and the dynamics of polymer-surfactant interactions.

We have a significant interest in the role that these colloidal dispersions can play in mediating solvent properties for enhancing separation and reaction processes in the chemical, metallurgical and biochemical industries. A major thrust of our research program, thus, is to explore novel techniques to optimize solvents for specific applications, and to characterize them in terms of the fundamental molecular processes responsible for the solvation properties of the structured solvents. The primary emphasis is on colloidal surfactant and polymer aggregates such as micelles and reversed micelles which provide a nonisotropic, microstructured environment for the selective interaction with targeted solutes in an otherwise homogeneous macrophase. We have, for instance, used reversed micelles to solubilize polar solutes such as proteins and amino acids in organic solvent extractants, block copolymer micelles for the removal of trace contaminants from surface and groundwaters, and two-phase aqueous polymer solutions for the selective partitioning of proteins. We are now also investigating ways in which we can tailor solvents for specific applications while at the same time reducing their propensity to enter the environment with air emissions and aqueous discharge streams. Colloidal magnetic fluids are being investigated as suitable reaction and separation media, as they can be heated effectively and more uniformly by microwave absorption of energy, and their flow can be directed by suitable application of magnetic fields, allowing novel separation and reaction configurations to be implemented.