Dinesh O. Shah
Ph.D., 1965, Columbia University (1970)
Professor Emeritus
Ph : 352-392-0877
shah@che.ufl.edu
425 Chemical Engineering Building
Faculty Web Page
Areas
Interfacial phenomena in engineering and biomedical systems
Molecular association in micelles, liquid crystals and microemulsions
Nanoparticles for superconductors and magnetic materials
Enzymic reactions at interfaces

Our research projects are in three major areas: biomedical, surfactant solutions and advanced materials. In the biomedical area, we investigate surface chemical aspects of polymer adsorption on contact lenses in relation to biolubrication and comfort in the eyes. We also study transdermal diffusion of local anesthestics.

In various engineering processes such as cleaning, lubrication or dispersions, the adsorption of surfactants at the interface is very important. The molecular aggregates of surfactants are commonly known as micelles. We have shown that the lifetime of micelles is related to their stability. The more stable micelles lead to decreased flux when a new surface is created. Thus, we have shown that the micelle stability significantly influences the foaming, droplet size in emulsions, wetting of textile fibers, and the rate of solubilization of oil in detergent solutions.

Nanoparticles of superconductors and magnetic materials can be produced using microemulsion processing. Here, the micro droplets of water can be used as microreactors. Two identical microemulsions containing different reactants are mixed together so as to produce nanoparticles upon collision and coalescence of micro droplets. The precipitation reaction leads to the formation of nanoparticles in these microreactors. We have further shown that such nanopowders when used as the raw material can produce high density superconductors which exhibit superior levitation due to greater Meissner effect. The magnetic flux does not go through such dense superconductors. We have further shown using electron microscopy that the grain-size is considerably larger in the nanoparticle derived samples as compared to the conventionally prepared samples. The research of our group has been supported by the National Science Foundation and Electric Power Research Institute as well as by several industrial companies (Alcon Laboratories, Alcoa, Kimberly-Clark, Kraft, Procter & Gamble Company).

Major Equipment
  • Brookhaven quasielastic light scattering spectrometer
  • Langmuir film balance
  • Contact angle goniometer
  • Perkin-Elmer fluorescence spectrophotometer
  • Pressure-jump, temperature-jump and stopped-flow instruments
 
Recent Publications
1. James-Smith, M.A., Shekhawat, D., Cheung, S., Moudgil, B.M. and Shah, D.O., “ Effect of Chain Length on Binding of Fatty Acids to Pluronics in Microemulsions,” Colloids and Surfaces B-Biointerfaces, 62(1) (2008) 5.
2. James-Smith, M.A., Shekhawat, D., Cheung, S., Moudgil, B.M. and Shah, D.O., “ Role of Ethylene Oxide and Propylene Oxide Groups of Pluronics in Binding of Fatty Acid to Pluronics in Microemulsions,” Journal of Surfactants and Detergents, 11(3) (2008) 237.
3 James-Smith, M.A., Shekhawat, D. and Shah, D.O., “ Importance of Micellar Lifetime and Sub-Micellar Aggregates in Detergency Processes,” Tenside Surfactants Detergents, 44(3) (2007) 142.
4. Morey, T.E., Modell, J.H., Shekhawat, D., Grand, T., Shah, D.O., Gravenstein, N., McGorray, S.P. and Dennis, D.M., “ Preparation and Anesthetic Properties of Propofol Microemulsions in Rats,” Anesthesiology, 104(6) (2006) 1184.
5. Paruchuri, V.K., Nalaskowski, J., Shah, D.O. and Miller, J.D., “ The Effects of Cosurfactants on Sodium Dodecyl Sulfate Micellar Structures at a Graphite Surface,” Colloids and Surface A: Physiochem. Eng. Aspects, 2722 (2006) 157.