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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: POSTERS Rheology

CPP 7.17: Poster

Montag, 25. Februar 2008, 16:45–19:00, Poster A

Single molecule probe diffusion in liquid crystalline films — •Benjamin Schulz, Jörg Schuster, and Christian von Borczyskowski — TU Chemnitz, Institut für Physik, 09107 Chemnitz

Liquid crystalline materials are widely used in modern displays. Image quality and switching speed of the display cells are critically influenced by details of the arrangement of the mesogenes at the interface. Thus, analytical techniques are required which are able to probe molecular orientation in liquid crystals on a nanoscale. We will present the first study on the use of single fluorescent dye probes which are especially tailored for the analysis of liquid crystalline materials on the single molecule level. Perylene dyes have been modified such, that the dyes align along the orientation of the mesogenes, and will thus, due to the orientation of their absorption and emission dipoles, probe the local orientation of the liquid crystal.

Diffusion trajectories of such dye probes in thin liquid crystalline films have been tracked by wide field microscopy techniques and analyzed following standard procedures [1]. The use of tailored probe molecules allows us to discriminate between homeotropic and homogeneous alignement of thin liquid crystalline films. By comparing diffusion properties of different dyes with variable alignment strength, details of the orientation of the films will be resolved in future. Here we present the comparison of the diffusion properties of two perylene derivatives, one strongly aligning and one not aligning.

[1] J. Schuster, F. Cichos, C. von Borczyskowski: Eur. Polymer J. 40 (2004), 993