Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 44: Charged Soft Matter I

CPP 44.3: Vortrag

Donnerstag, 3. April 2014, 10:00–10:15, ZEU 118

Adsorption Behavior of Catanionic Surfactant Mixtures at the Air-Water Interface and in Freestanding Foam Films — •Heiko Fauser, Martin Uhlig, and Regine von Klitzing — Technische Universität Berlin, Stranski-Laboratorium Institut für Chemie, Straße des 17. Juni 124, 10623 Berlin

Although the application of liquid foams is widespread, too little is yet understood about their stability control. One way to tune liquid foam films is the use of oppositely charged surfactant mixtures. Due to electrostatic attraction highly surface active aggregates are formed. Our study addresses the question of whether the adsorption of equimolar or irregular catanionic complexes and thus a variation in surface composition governs foam film properties.

Mixtures of the anionic surfactant SDS with the cationic C12TAB are investigated. We compare the adsorption behavior at liquid/air interfaces and in freestanding foam films at different total concentrations and varying mixing ratio.

Surface tension measurements reveal a high surface activity for these mixtures already at very low concentrations. The same high surface activity is detected over a broad regime varying the mixing ratio. In contrast Thin Film Pressure Balance measurements reveal a variation in the foam film properties. Foam film thickness and stability varies with the mixing ratio. We also discuss a strong impact on adsorption kinetics and foaming of these mixtures.

This shows that for different catanionic surfactant mixtures surface composition and foam film properties changes.