Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: Poster: Charged Soft Matter

CPP 22.10: Poster

Wednesday, March 28, 2012, 11:00–13:00, Poster A

Effective interactions in electrolyte solutions — •Markus Bier and S. Dietrich — Max-Planck-Institut IS, Stuttgart, Germany

The effective interactions between walls or colloidal particles are known to be significantly influenced by the properties of a liquid medium in contact. Well-known examples are dispersion forces, which are determined by the permittivity, electrostatic forces, which become short-ranged due to the screening of the Coulomb potential by ions, and solvation forces, which arise due to solvent adsorption or desorption. Commonly these contributions to the effective interactions are assumed to be independent, i.e. the effective interactions are expected to be a simple superposition. However, recently experimental observations for a binary liquid mixture containing salt were reported [1] which cannot be understood by assuming solvation forces being uncoupled from the screened electrostatic forces. Here a possible mechanism [2] is discussed in terms of which all experimental evidence can be explained consistently.

• [1] U. Nellen, J. Dietrich, L. Helden, S. Chodankar, K. Nygard, J. van der Veen and C. Bechinger, Soft Matter 7, 5360 (2011).
• [2] M. Bier, A. Gambassi, M. Oettel and S. Dietrich, EPL 95, 60001 (2011).