Professor Wasan, who is currently serving as editor-in-chief of the Journal of Colloid and Interface Science, has research interests in the areas of interfacial and colloidal phenomena, foams, emulsions and dispersions, and food and environmental technologies. His present research activities in these areas are:
Thin Liquid Films, Foams, Emulsions and Nano-particle Suspensions
Stability of thin liquid films containing surfactants, proteins, polymer latexes, or nano-particles is being investigated using reflected light microinterferometric techniques. These experiments have revealed for the first time the formation of "ordered" microstructures inside the film over distances of the order of one thousand Angstroms. This microstructure within the film is shown to provide a new mechanism for stabilizing dispersed phase systems. Monte Carlo and Molecular Dynamic simulations are conducted to verify the experimental observations. Important technological factors affecting the ordered microstructure formation and stability of colloidal dispersions such as foam, and emulsion and colloidal suspensions using nanoparticles are being investigated. The National Science Foundation, which is funding his research, awarded Dr. Wasan a special creativity award for this work and he was elected to the National Academy of Engineeirng, the highest professional honor for engineers, for his research accomplishments.
Wetting, Spreading and Adhesion of Nanofluids on Solid Surfaces
Mechanisms of wetting, spreading and adhesion of fluids containing nanoparticles such as surfactant micelles, proteins and macromolecules are found to be different than those from wetting of normal fluids. A new mechanism of detergency involving nanoparticles structuring phenomena is being investigated. This research has applications in cleaning of hard surfaces such as silicon wafers and soil remediation as well as in adhesion of living cells on solid surfaces and fabrication of nanostructured materials such as photonic crystals. This research was highlighted in his paper published in the journal Nature in 2003.
Film Rheology and its Applications
This research program involves the development and use of a novel experimental technique called film rheometry to measure both the dynamic film tension and film elasticity of surfactant, proteins and polymeric systems. Applications of these properties can be used to control dispersed phase systems such as polymer emulsion stabilization, coalescence of water-in-oil emulsions, foam stability, antifoaming, and thinning of films between bubbles or drops.
Environmental research is conducted on the remediation of high-level and low-level nuclear wastes, which will be immobilized into glass. Major inorganic and organic chemicals in these wastes can cause foaming and gas entrainment problems that ultimately result in excessive shutdown and loss of attainment. The specific aim of this research, which is supported by the U.S. Department of Energy, is to develop a fundamental understanding of the physicochemical mechanisms that produce foaming and air-entrainment in the radioactive waste separation as immobilization process and to develop and test advanced antifoam/defoamimg rheology modifier agents.
Many food formulations including beverages such as beer, cappuccino and milk coffee employ protein stabilized foams and emulsions. Our research in food colloids is directed towards using experimental techniques already available in our laboratory to study the foam and emulsion quality and stability under various conditions in a variety of food dispersions. This work is supported by a number of indstrial organizations.