Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: Polymerphysics II
CPP 30.3: Vortrag
Donnerstag, 28. Februar 2008, 14:30–14:45, C 130
Dynamics in polymer networks containing liquid crystal — •Rachid Hadji1,2,3, Silke Rathgeber1, Amina Négadi2, and Ulrich Maschke3 — 1Max-Planck-Institute for Polymer Research, Polymer Physics, 55128 Mainz, Germany. — 2Université Aboubakr Belkaïd, Laboratoire de Recherche sur les Macromolécules, 13000 Tlemcen, Algeria. — 3Université des Sciences et Technologies de Lille, Laboratoire de Chimie Macromoléculaire, 59655 Villeneuve d'Ascq Cedex, France.
Polymer networks filled with liquid crystal are of interest due to their actuatoric properties but also due to their possible optical applications. Their anisotropic optical properties allow the switching from a transparent to an opaque state by alignment in an external electrical field. Changing the temperature through the disorder/order transition of the liquid crystal leads to a deswelling/swelling of the network which can be used for actuatoric applications. We studied the molecular dynamics of polymer networks containing different amounts of liquid crystal with dielectric spectroscopy (DS) and mechanical spectroscopy at the nematic-isotropic transition of the liquid crystal. We also followed the phase transitions of the systems by dynamic scanning calorimetry. The networks under investigation were poly(n-butyl acrylate) networks filled with the commercial liquid crystals 5CB and E7, respectively. We were able to follow the dynamical changes occuring in the polymeric matrix as well as in the liquid crystalline solvent at the nematic-isotropic transition. In addition we studied the effect of the degree of sterical hindrance by changing the crosslink density.