Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Poster: Interfaces and Thin Films

CPP 19.7: Poster

Dienstag, 15. März 2011, 18:00–20:00, P2

Interactions and stability of foam films from oppositely charged surfactant mixtures — •Heiko Fauser, Nora Kristen-Hochrein, Natascha Schelero, and Regine von Klitzing — Stranski-Laboratorium, Institut für Chemie TU-Berlin, Strasse des 17. Juni 124, 10623 Berlin, Deutschland

Mixtures of cationic and anionic surfactants are widely used in industrial processes and products. Until this date mainly the adsorption behavior of oppositely charged surfactants at liquid and solid surfaces has been investigated. In order to understand adsorption at foam films it is important to investigate free-standing foam films. A measurement of the interactions between two opposing foam-film interfaces is the disjoining pressure, which is considered to be the sum of repulsive electrostatic and steric forces, as well as attractive van der Waals forces. The disjoining pressure is measured with a so called Thin Film Pressure Balance.

Mixtures of oppositely charged surfactants tend to show interesting properties and behavior in terms of stability and thickness of the free-standing films. For example is the formation of a Common Black Film or a much thinner but more stable Newton Black Film governed by the concentration ratio of the surfactant mixture.

Also the question how supplement measurements of other physical properties like surface tension or surface rheology can support to understand our results and help to develop a more precise description of such surfactant mixtures is taken into account.