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Proceedings Paper

Determination of azimuthal anchoring energy in grating-aligned twisted nematic liquid crystal layers
Author(s): Emma L. Wood; G. W. Bradberry; P. S. Cann; J. Roy Sambles
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Paper Abstract

In this work sinusoidal diffraction gratings with a range of pitches and amplitudes are used to algin nematic liquid crystal layers in a twisted homogeneous configuration. The grating profiles are accurately characterized using optical surface plasmon polariton spectroscopy which then allows a calculation of the anchoring energy as predicted by the simple Berreman expression. The experimental Rapini-Papoular anchoring energy is also obtained by a measurement of the director twist away from the alignment direction at room temperature. A linear relationship is found between the two anchoring energies except when it falls below 4 X 10-7Jm-2. Noticeably, the correlation between the two theories is hot unity, if room temperature elastic constants are used in the calculation. This apparent inconsistency is explained if the effect of surface memory on the system is considered. Indeed if elastic constant, corresponding to a higher temperature, at which surface memory effects are absent, are used in the Berreman expression, good agreement between the predicted and experimentally measured energies is found.

Paper Details

Date Published: 1 February 1998
PDF: 7 pages
Proc. SPIE 3318, Liquid Crystals: Physics, Technology, and Applications, (1 February 1998); doi: 10.1117/12.299984
Show Author Affiliations
Emma L. Wood, Exeter Univ. (United Kingdom)
G. W. Bradberry, Exeter Univ. (United Kingdom)
P. S. Cann, Exeter Univ. (United Kingdom)
J. Roy Sambles, Exeter Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 3318:
Liquid Crystals: Physics, Technology, and Applications
Jolanta Rutkowska; Stanislaw J. Klosowicz; Jerzy Zielinski; Jozef Zmija, Editor(s)

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