Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 10: Interfaces and Thin Films II

CPP 10.2: Talk

Tuesday, March 27, 2012, 10:00–10:15, C 130

Interactions and stability of foam films from oppositely charged polyelectrolyte/surfactant mixtures — •Nora Kristen-Hochrein, Heiko Fauser, Martin Uhlig, and Regine von Klitzing — Stranski-Laboratorium, Institut für Chemie, TU Berlin, Germany

Polyelectrolyte/surfactant mixtures in foams play an important role in many technical applications. To control the properties of the foam it is important to investigate single foam films. A measure of the interactions between the two film interfaces is the disjoining pressure, which is the sum of electrostatic, van der Waals and steric forces. The disjoining pressure as a function of film thickness is measured with a Thin Film Pressure Balance (TFPB). In this study we focus on the influence of negatively charged polyelectrolytes on foam films stabilized with cationic surfactant. At low polyelectrolyte concentrations the charge at the surface is positive. With increasing amount of polyelectrolyte the charge of the complexes is reduced and then reversed. However, surface characterization indicates that no charge reversal occurs at the film interfaces. To test the influence of the polyelectrolyte and surfactant hydrophobicity[1,2], results on the stability of films with different polyelectrolytes and surfactants are shown and compared with surface tension and elasticity and neutron reflectometry measurements.

[1] N. Kristen, V. Simulescu, A. Vüllings, A. Laschewsky, R. Miller and R. v. Klitzing, J. Phys. Chem B (2009) 113 7985.

[2] N. Kristen-Hochrein, A. Laschewsky, R. Miller, R. v. Klitzing, J. Phys. Chem B, (2011) DOI: 10.1021/jp206964k