Dresden 2009 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: POSTERS Colloids and Liquids

CPP 39.33: Poster

Thursday, March 26, 2009, 17:00–19:30, P3

Time-resolved optical measurement of director dynamics in electroconvection — •Stephan Messlinger, Achim Sack, Wolfgang Schöpf, and Ingo Rehberg — Experimentalphysik V, Universität Bayreuth, Bayreuth, Germany

We investigate the time-dependent behavior of electroconvective patterns in liquid crystal cells [1-3] with a shadowgraph setup. Time resolution is achieved by a stroboscopic illumination [4], phase-locked to the periodic driving voltage applied to the cell. By varying the illumination phase relative to the driving voltage, the temporal modulation of the electroconvective patterns can be visualized. We present a harmonic analysis of the temporal behaviour near the convection onset, both in the dielectric and in the conductive regime.

[1] I. Rehberg, B. L. Winkler, M. de la Torre Juárez, S. Rasenat and W. Schöpf, Adv. Solid State Phys. 29, 35 (1989).

[2] P. G. de Gennes and J. Prost, The Physics of Liquid Crystals (Clarendon Press, Oxford, 1993).

[3] A. Buka and L. Kramer, Pattern Formation in Liquid Crystals (Springer, New York, 1996).

[4] U. Schneider, M. de la Torre Juárez, W. Zimmermann and I. Rehberg, Phys. Rev. A 46, 1009, (1992).