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Proceedings Paper

Surface electrical potential of the aligning polymer substrates and dielectric properties of LC layers
Author(s): R. Kravchuk; Oleg V. Yaroshchuk; O. Kovalchuk; P. Karageorgiev; B. Stiller; Joachim Stumpe
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Paper Abstract

UV light influence on the surface potential φs of poly(vinylcinnamate) (PVCN) layers widely used for liquid crystal (LC) photoalignment is investigated. In case when PVCN film is spin coated on the ITO electrodes the surface potential changes under irradiation in both PVCN aligning film and ITO coating. The measured increment of the surface potential changes under irradiation in both PVCN aligning film and ITO coating. The measured increment of the surface potential Δφs=400 mV is mainly cuased by the photoconductivity of ITO electrodes, whereas the part caused by PVCN substrate is at least one order of magnitude lower. The relaxation time of Δφs for the ITO-PVCN coatings was estimated to be about 1 h. The induced potential may substantially modify dielectric properties of the aligned LC layers and its anchoring characteristics when the freshly irradiated substrates are used. On the contrary, this influence is weak when the substrates are irradiated several hours before the use for LC alignment.

Paper Details

Date Published: 11 December 2002
PDF: 7 pages
Proc. SPIE 4938, Selected Papers from the International Conference on Spectroscopy of Molecules and Crystals, (11 December 2002); doi: 10.1117/12.486657
Show Author Affiliations
R. Kravchuk, Institute of Physics (Ukraine)
Oleg V. Yaroshchuk, Institute of Physics (Ukraine)
O. Kovalchuk, Institute of Physics (Ukraine)
P. Karageorgiev, Fraunhofer-Institute for Applied Polymer Research (Germany)
B. Stiller, Fraunhofer-Institute for Applied Polymer Research (Germany)
Joachim Stumpe, Fraunhofer-Institute for Applied Polymer Research (Germany)


Published in SPIE Proceedings Vol. 4938:
Selected Papers from the International Conference on Spectroscopy of Molecules and Crystals
Galina A. Puchkovska; Sergey A. Kostyukevych, Editor(s)

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