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  • [ December 05, 2018]

    Emulsion and foam stability: one drop and bubble at a time

  • Speaker:
    Gerald G. Fuller
    Dec. 11, 2018
    Room 210, COE Building No.1
    Dongxiao Zhang
  • Abstract
  • The stability of emulsions and foams are affected by a number of physical processes. As thin liquid films surrounding bubbles and drops drain, film rupture can occur, leading to coalescence and to coarsening. A common approach to appreciating stability in these systems is to create a bulk emulsion or foam and to follow the rate of creaming (for an emulsion) or collapse and drainage (for a foam). In this lecture, an alternative approach is described whereby individual bubbles and drops are monitored as they approach a fluid/fluid interface until coalescence ensues. These measurements utilize a newly developed instrument, the Dynamic Fluid Film Interferometer (DFI) where draining film thicknesses can be measured in space and time as well as the pressure drop (Laplace pressure) across the interface. Application of the DFI to study two problems is presented: (1) coalescence of oil/water emulsions in the presence of asphaltenes and (2) antifoaming of lubricating oils.
  • Biography
  • Gerald Fuller is the Fletcher Jones Professor of Chemical Engineering at Stanford University. He joined Stanford in 1980 following his graduate work at Caltech where he acquired his MS and PhD degrees. His undergraduate education was obtained at the University of Calgary, Canada. Professor Fuller's interests lie in studies of rheology and interfacial fluid mechanics. His work has been recognized by receipt of the Bingham Medal of The Society of Rheology, membership in the National Academy of Engineering, election to the American Academy of Arts and Science, and honorary doctorates from the Universities of Crete, Greece, and Leuven, Belgium. He presently serves as the General Secretary to the International Committee on Rheology.