Influence of interfacial rheology on foam and emulsion properties

Foams and emulsions are stabilized by surfactant monolayers that adsorb at the air-water and oil-water interfaces, respectively. As a result of monola yer adsorption, the interfaces become viscoelastic. We will describe experi ments showing that foaming, emulsification, foam and emulsion stability, ar e strongly dependent upon the value of compression elasticity and viscosity . This will include excited surface wave devices for the measurement of sur face viscoelasticity and thin film videointerferometry for the study of mod el films between air bubbles and emulsion drops. (C) 2000 Elsevier Science B.V. All rights reserved.