Adsorption dynamics, interfacial elasticity and emulsion stability: The scientific basis of the FASES map project

The set-up of methodologies for stabilising/de-stabilising emulsions is one of the most important goals for the technology of dispersed systems. To this aim it is necessary to understand the role and the behaviour of the adsorption layer, which is always present in these systems at the liquid-liquid interface between the dispersed droplets an the matrix. In fact, aggregation and coalescence are the basic mechanisms underlying the destabilisation, both mechanisms being mainly controlled by the characteristics of the interfacial layer. These research topics are addressed by the project FASES (Fundamental and Applied Studies in Emulsion Stability) which has recently been approved by ESA in the framework of the Microgravity Application Programme (MAP). Hereafter a brief description of the project is given underlining its microgravity relevance and the experimental methods. Moreover, selected aspects or the stability of emulsions which involve the dynamics of adsorption are discussed, in order to clarify the scientific basis of the project. Finally, some recent results obtained about the adsorption dynamics and the interfacial rheology of specific classes of soluble surfactants are summarised.