Julian van Megen gewinnt auf der European Detergence Conference in Fulda einen Posterpreis.
Titel: Study of adsorption layers of surfactant mixtures on solid surfaces by atomic force microscopy
In detergents and cleaners surfactant mixtures are used due to an enhanced performance compared to the single components. This regards dispersing and emulsification processes, dispersion stability and wetting properties. In these processes interactions between the different surfactants and various surfaces lead to a complex adsorption behaviour. The reason for the synergy of surfactant mixtures is not fully understood. Therefore a better knowledge of surfactant interaction and adsorption mechanisms in mixtures is needed.
Atomic force microscopy (AFM) was applied to mixtures of high and low molecular weight nonionic and ionic surfactants at liquid/solid interfaces. It was possible to analyse the structure and composition of adsorption layers. The results provided information about different interactions dependent on surface polarity, surfactant concentration and the character of the low molecular weight component. Simple models of the adsorption out of surfactant mixtures were derived from the observed structures. In addition surface tension and dynamic light scattering measurements were carried out to study the bulk phase and the liquid/air interface. The results at different interfaces give further insights into the interaction between the surfactants with regard to washing and cleaning processes.