Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 42: Colloids and Complex Liquids I

CPP 42.4: Vortrag

Donnerstag, 25. März 2010, 12:00–12:15, H39

Role of surface charges on structure formation in confined colloidal solutions — •Stefan Grandner and Sabine H. L. Klapp — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstraße 36, D-10623 Berlin, Germany

The impact of surface charges on structural effects in confined, charged colloidal suspensions is addressed in grand-canonical Monte-Carlo simulations using a corse-grained model (DLVO). These investigations are motivated by Colloidal-Probe Atomic-Force-Microscope experiments where enhanced amplitudes of the structural forces are obtained for increased surface charges. Whereas various established approaches of the interaction between macroions and charged walls did not reproduce this behavior, we could verify it within linearized Poisson-Boltzmann theory using a modified fluid-wall interaction which takes additional wall counterions into account [1]. The main difference to former models is the wall charge dependence of the wall screening parameter yielding a non-monotonic behavior of the repulsion. Furthermore we explore the impact of charged walls on particle ordering [2], where we expect nontrivial consequences on the lateral order of the layered suspension as compared to uncharged surfaces [3].

[1] S. Grandner, Y. Zeng, R. v. Klitzing, and S. H. L. Klapp, J. Chem. Phys. 131, 154702 (2009). [2] B. Fazelabdolabadi, J. Y. Walz, and P. R. Van Tassel, J. Phys. Chem. B 113, 13860 (2009). [3] S. Grandner and S. H. L. Klapp, J. Chem. Phys. 129, 244703 (2008).