Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: Poster: Glass Transition and Dynamics of Liquids

CPP 22.6: Poster

Dienstag, 15. März 2011, 18:00–20:00, P2

Dielectric relaxation of a nematic liquid crystal dispersed in a polar or non-polar polymer matrix — Lakshmi Meena Ganesan, •Lars Holländer, Werner Wirges, Peter Frübing, and Reimund Gerhard — Universität Potsdam

Polymer-dispersed liquid-crystal (PDLC) films were prepared from a nematic liquid crystal (LC) and polar poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) or non-polar poly(methyl methacrylate) (PMMA) as polymer matrix materials. During the preparation process, micrometer-sized droplets of LC are formed inside the polymer matrices.

The influence of the polymer matrix on the dielectric behavior of the LC was investigated by means of dielectric relaxation spectroscopy. From activation-energy calculations, it is assumed that the LC in the center of the droplets behaves like bulk material. Nevertheless, the angular motions of the dipole moments of the nematogen are slowed down in PDLC films by interfacial effects. This hindrance in motion is more pronounced in samples of polar P(VDF-TrFE) than in samples of non-polar PMMA and indicates a stronger interaction between the liquid-crystal molecules and the polar polymer molecules.