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Proceedings Paper

Electric birefringence of some nematic liquid crystals having hexyl tail
Author(s): H. Khoshsima; H. Tajalli; A. Ghanadzadeh; R. Dabrowski
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Paper Abstract

Electro-optical Kerr effect data have been obtained for 6CB, 6CHBT, 6PCH and 6BOBT at temperatures above the nematic-isotropic transition temperature. All the compounds had a positive Kerr constant which increased with decreasing of temperature. The second order phase transition temperatures, T*, were determined for these compounds. The linear dependence of (T - T*)-1 on the Kerr constant is found to be relatively in good agreement with the predications of the Landau-De Gennes model. The replacement of aromatic ring by a flexible cyclohexyl group and or by a bulkier bicyclooctane has a marked effect on the birefringence. Hexyl 4-(4-isothiocyanato-phenyl) bicycle [2,2,2] octane, 6BOBT, with the highest transition temperature had the lowest Kerr constant. In contrast, hexyl cyanobiphenyl,6CB, showed the largest Kerr constant (6BOBT → 6CHBT ≈ 6PCH → 6CB). The effect of the rigid core and polar head group of the liquid crystals was investigated.

Paper Details

Date Published: 6 October 2005
PDF: 9 pages
Proc. SPIE 5947, Liquid Crystals: Optics and Applications, 59470P (6 October 2005); doi: 10.1117/12.620884
Show Author Affiliations
H. Khoshsima, Tabriz Univ. (Iran)
H. Tajalli, Tabriz Univ. (Iran)
A. Ghanadzadeh, Tabriz Univ. (Iran)
Guilan Univ. (Iran)
R. Dabrowski, Military Technical Academy (Poland)


Published in SPIE Proceedings Vol. 5947:
Liquid Crystals: Optics and Applications
Tomasz R. Wolinski; Marc Warenghem; Shin-Tson Wu, Editor(s)

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