Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Confined Fluids
CPP 12.5: Vortrag
Dienstag, 26. Februar 2008, 12:00–12:15, C 230
Crystallization in layered films of confined charged colloids — •Stefan Grandner1 and Sabine H. L. Klapp1,2 — 1Stranski-Laboratorium, Technische Universität Berlin, Straße des 17. Juni 115, D-10623 Berlin, Germany — 2Institut für theoretische Physik, Technische Universität Berlin, Hardenbergstraße 36, D-10623 Berlin, Germany
We consider a system of spherical charged colloids between two parallel walls. A characteristic property of such colloids is the screening of the Coulomb potential of the macroions due to the counterions and additional salt, which we take into account via DLVO theory. An earlier comparison of Monte-Carlo results with colloidal probe AFM experiments has demonstrated the applicability of the DLVO potential for confined systems [1]. Typical for confined fluids is a layering parallel to the walls, which was observed for charged colloids as well [1,2]. In our current investigations we employ grand canonical Monte-Carlo simulations to study the in-plane structure in dense states. In particular, by computing bond angle order parameters we search for evidence of crystallization in the layers. Previous work for bilayers discovered several crystal-like structures such as square, hexagonal or rhombic ordering [3]. Furthermore we discuss the dependence of the onset of crystallization on pore size and bulk density.
[1] S. H. L. Klapp, D. Qu, and R. v. Klitzing, J. Phys. Chem. B 111, 1296-1303 (2007).
[2] M. Kittner, and S. H. L. Klapp, J. Chem. Phys. 126, 154902 (2007).
[3] R. Messina, and H. Löwen, Phys. Rev. Lett. 91, 146101 (2003).