Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 33: Poster Session III

CPP 33.19: Poster

Dienstag, 13. März 2018, 14:00–16:00, Poster C

Structure properties of biaxial phases formed by mixtures composed of uniaxial liquid crystal particles. — Robert Skutnik, •Louis Lehmann, Sergej Püschel-Schlotthauer, and Martin Schoen — Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Sekr. C7, Straße des 17. Juni 135, Berlin 10623, Germany

Liquid crystals consist of organic molecules of anisotropic shapes. With respect to their shape, they can be classified as disc- and rod-like particles. Both types of particles undergo an isotropic-nematic phase transition. In the nematic phase, the particles align parallel to each other and exhibit thereby a long-range orientational order. In mixtures of discotics and rods, the favored configuration of two separate disc-like particles or two rod-like particles remains parallel. However, rod-like particles align perpendicularly to the disc-like particles with respect to their symmetry axes. In order to study the phase transition of such mixtures, we perform isothermal-isobaric Monte Carlo simulations where the interparticle interactions are modeled by an orientation-dependent Lennard-Jones potential. Here we present a phase diagram of a binary mixture including a biaxial nematic phase as well as a mixture of a uniaxial nematic phase and an isotropic phase with reduced degrees of freedom. We use finite-size scaling theory to identify the phase transition temperatures and use different order parameters to analyze the structure of the mixture.