Dresden 2009 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: POSTERS Colloids and Liquids

CPP 39.4: Poster

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

Frequency dependent deformation of liquid crystal droplets in an external electric field — •Günter K. Auernhammer, Jinyu Zhao, and Doris Vollmer — Max-Planck-Insitut für Polymerforschung, Ackermannweg 10, 55128 Mainz

Nematic drops suspended in the isotropic phase of the same substance were subjected to alternating electrical fields of varying frequency. The system was carefully kept in the isotropic-nematic coexistence region, which was broadened due to small amounts of non-mesogenic additives. Whereas the droplets remained spherical at low (order of 10 Hz) and high frequencies (in the kHz range), at intermediate frequencies, we observed a marked flattening of the droplet in the plane perpendicular to the applied field. The deformation of the liquid crystal droplets occurred both in substances with positive and negative dielectric anisotropy. We show that this frequency dependent deformation can be modeled with a combination of the leaky dielectric model and screening of the applied electric field due to the finite conductivity.