ABSTRACT
The thermodynamic description of adsorption layers is an important prerequisite for a quantitative understanding of any processes going on at liquid interfaces. It provides equations of state which express the surface pressure as the function of surface layer composition, and the corresponding adsorption isotherms which determine the dependence of the adsorption of each dissolved component on their bulk concentrations. The knowledge of adsorption layer properties at the air/solution interface is of key importance for understanding the formation and stability of foams and foam films. The formation and properties of protein adsorption layers at the solution/air surface are quite different from those of surfactants. The shear rheology can be studied for quite a number of systems, adsorbed layers as well as spread monolayers containing polymers, proteins, and surfactants. The surface dilational viscoelasticity of liquid interfaces is a direct consequence of the surface tension concept and is related to the reaction of the interfacial layer to the imposed external disturbances.
