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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
Engineering, 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 Technologies
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.
Food Colloids
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 industrial organizations. |
