Fast adsorption at the liquid-gas interface

Adsorption of surfactants with short hydrocarbon chains at the liquid-gas interface occurs mainly within the millisecond time range. In this case conventional methods proposed to investigate slower adsorption processes cannot be applied and one is forced to use more complicated experimental techniques where basic features of the liquid flow in the apparatus have to be taken into account. This work contains a brief survey of the history of adsorption kinetics studies and a short discussion of some general ideas concerning surfactant transfer from the bulk phase to the surface layer. However, the main attention is paid to the adsorption kinetics from aqueous solutions of alcohols. These systems have been used rather frequently as physical models in the course of studies of the non-micellar surfactant solutions. Nevertheless, even in this relatively simple case data obtained by different authors contradict each other. It is shown that the main difficulties arise from using incomplete hydrodynamic models at the interpretation of the results of measurements of the dynamic surface tension. Application of experimental methods based on a more elaborated hydrodynamic theory leads to a simple diffusion adsorption mechanism for alcohols.