Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Poster: Focus: Van der Waals at soft matter interfaces: structure and dynamics

CPP 37.1: Poster

Mittwoch, 13. März 2013, 16:30–18:30, Poster C

Structure and Dynamics in Frustrated Liquid Crystal Films Influenced by Subsurface Substrate Material — •Kathrin Radscheit, Daniela Täuber, and Christian von Borczyskowski — nanoMA, TU-Chemnitz, Institut für Physik

Liquid crystals are known to be very sensitive to chemical and topological properties of confining interfaces. Recently we found an influence of the subsurface substrate composition on the structure in thin frustrated 8CB liquid crystal films on Si with native or 100 nm thermal oxide [1]. Observation in polarization resolved reflected light during heating from the smectic A to the nematic phase and subsequent cooling, reveales different timescales of the phase transition of thin 8CB films on the two types of substrate. We ascribe the observed differences to van der Waals interactions with the underlying silicon in case of the native oxide, whereas the thermal oxide suffices to shield those interactions. Additional information about the dynamics in thin liquid crystal films is obtained from correlations of s- and p-polarization resolved fluorescence intensities from diffusing tracer molecules, extending previous studies in unpolarized light [2].

[1] B. Schulz, D. Täuber, J. Schuster, T. Baumgärtel and C. von Borczyskowski, Soft Matter 7 (2011) 7431. [2] B. Schulz, D. Täuber, F. Friedriszik, H. Graaf, J. Schuster and C. von Borczyskowski, PCCP 12 (2010) 11555.