Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 34: Colloids and Complex Liquids II
CPP 34.9: Vortrag
Donnerstag, 29. März 2012, 17:30–17:45, C 130
Self-assembled nematic defect-structures for Janus beads — •Michael Melle1, Sergej Schlotthauer1, and Martin Schoen1,2 — 1Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany — 2Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC 27695, U.S.A.
We present Monte Carlo simulations of a colloid embedded in a nematic liquid crystal host. Employing different alignment scenarios for the liquid crystal molecules on the surface of the colloid our model is able to reproduce known defect structures of the liquid crystal, such as Saturn ring, surface ring, or Boojum defect to high accuracy and over a wide range of parameters like temperature, pressure or strength of alignment. However, the main focus of this study is on inhomogeneous, spherical colloids such as Janus beads. Despite the large interest that Janus beads have attracted in the last decade, almost no work has been done on the defect structures generated by them. Therefore, we also develop different alignments for different sides of the colloid. We are able to reproduce experimentally known defect structures for Janus beads. In addition, we also predict new topologies. Furthermore, we see transitions between different defect structures induced by a slight decrease of temperature, which is a novel observation as well.