Regensburg 2013 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Poster: Interfaces and Thin Films (joint session with DECHEMA and VDI)

CPP 9.11: Poster

Monday, March 11, 2013, 17:30–19:30, Poster C

Adsorption Behavior of Catanionic Surfactant Mixtures at the air/liquid interface — •Martin Uhlig, Heiko Fauser, and Regine v. Klitzing — Stranski-Laboratorium, Department of Chemistry, TU Berlin, Straße des 17. Juni 124 D-10623 Berlin, Germany

The strong synergism of catanionic surfactant mixtures is known for a long time. The synergism allows to reduce the expended amount of surfactant, thus making catanionic surfactant mixtures eco-friendly. Therefore, these mixtures are of great interest for a broad field of applications. However, only very recently basic research was performed about the stability of foams formed with these mixtures. It was shown that the formation of surface active complexes and aggregates strongly enhances the adsorption at liquid-air interfaces and thus the foamstability [1].

Literature also shows that mixtures of surfactants with unequal chain length differ in surface properties in comparison to mixtures with equal chain length [2]. Hence, the focus of our work is on the influence of the surfactant alkyl chain length on the foam properties. We investigate catanionic mixtures from two commmon surfactant types, sodium alkyl sulfates and quarternary alkylammonium bromides. Both surface tension and the surface elasticity of mixtures with both matching chain length and mismatching chain length are investigated. Studies about the correlation between adsorbed amount of surfactants, interactions in thin foam films, foamability and foam stability are in progress.

[1] Varade, D. et.al.; Soft Matter, 2011, 7, 6557-6570

[2] Patist, A. et.al.; Langmuir, 1997, 13, 432-434