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 monolayer adsorption, the interfaces become viscoelastic. We will describe experiments showing that foaming, emulsification, foam and emulsion stability, are strongly dependent upon the value of compression elasticity and viscosity. This will include excited surface wave devices for the measurement of surface viscoelasticity and thin film videointerferometry for the study of model films between air bubbles and emulsion drops. (C) 2000 Elsevier Science B.V. All rights reserved.