Dresden 2009 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: POSTERS Polymer Physics

CPP 13.19: Poster

Dienstag, 24. März 2009, 14:00–16:30, P3

Infrared Transition Moment Orientational Analysis on Liquid Single Crystal Nematic Elastomers — •Wilhelm Kossack¹, Periklis Papadopoulos¹, Felicitas Brömmel², Heino Finkelmann², and Friedrich Kremer¹ — ¹Universität Leipzig, Institut für Experimentelle Physik I, Linnéstr. 5, 04103 Leipzig — ²Albert-Ludwigs-Universität Freiburg, Institute for Makromolecular Chemistry, Stefan Meier-Str. 31, 79104 Freiburg

Liquid Single Crystal Nematic Elastomers (LSCNE) form a novel class of materials combining the properties of liquid crystals with elastomeric networks and in which the crystalline order is extended to and stabilized on a macroscopic scale (∼cm²). In order to determine mean orientation and molecular order parameter of the different molecular moieties (mesogen, polymer backbone, etc.) IR-Transition Moment Orientational Analysis (IR-TMOA) is employed. This technique takes advantage from the specifity of the IR spectral range. Based on the measurements of the transmission dependence of polarization and an intentionally adjusted inclination of the sample numerical analysis of Fresnel-equations enables one to determine seperately real and imaginary part of the refractive index n^*. From that mean orientation and molecular order parameter of the molecular moieties, represented by different absorption bands, are deduced. As further refinement the sample can be mechanically stretched during the IR measurements. By that the microscopic response to macroscopic excitation can be unraveled and phenomena like elastic memory effects and the phase relationships in reorientation of the molecular units can be traced.