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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:04 |
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Conference: Bucharest University Faculty of Physics 2011 Meeting
Section: Polymer Physics
Title:
Fast Switching Effects in Nematic Liquid Crystals
Authors:
Gentiana Heimann, Gabriela Despan
Affiliation:
University of Bucharest, Faculty of Physics, P.O.BOX.MG-11, Bucharest, Romania
E-mail
Keywords:
polymeric materials, nematic liquid crystals, electro-optic effect
Abstract:
The switching between ON and OFF states of a nematic liquid crystal pixel can be controlled with the well-known electro-optic effect. This effect presents a relatively fast response at switching on the applied voltage, but a slow response time at switching it off. Here we present a choice of materials, cell geometries, surface preparations, and types of the applied voltage which leads to a very fast switch off time for a nematic liquid crystal cell. A thin film of plasma polymerized polymer having aromatic rings induces a stronger planar anchoring of cyanobiphenyl liquid crystals. Because of an asymmetric conduction of the liquid crystal cell, alternating voltages generate a transient electrically charged layer at the polyaniline/liquid crystal interface. This film favors an increase of the anchoring properties towards the bulk, while significantly lowering the relaxation time and increasing the contrast ratio.
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