Title

Fast switching near a smectic-to-nematic phase transition

Authors

Authors

S. Gauza; A. Parish; S. T. Wu; A. Spadlo;R. Dabrowski

Comments

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Abbreviated Journal Title

Liq. Cryst.

Keywords

high birefringence; isothiocyanato phenyl-tolanes; smectic-nematic phase; transition; TOLANE LIQUID-CRYSTALS; OPTICAL-PROPERTIES; MIXTURES; BICOMPONENT; Chemistry, Multidisciplinary; Crystallography; Materials Science, ; Multidisciplinary

Abstract

We have designed, synthesised and evaluated the physical properties of high-birefringence (Delta n) isothiocyanato phenyl-tolane and terphenyl liquid crystals. These compounds exhibit a Delta n similar to 0.36-0.52 at room temperature and wavelength lambda=633nm. A different mesomorphic sequence was observed depending on the terminal alkyl chain length. Compounds with a longer chain show smectic and nematic phases, whereas short-chain homologues only exhibit a nematic phase. In the vicinity of the nematic-to-smectic transition, the viscoelastic coefficient decreases, instead of increases, as the temperature decreases. The observed change is as large as 75% for the 4'-(3,5-difluoro-4-isothiocyanatophenylethynyl)-4-pentylbiphenyl compound studied. This behaviour is useful for improving the response time of a liquid crystal device, if the operating temperature can be controlled accurately.

Journal Title

Liquid Crystals

Volume

35

Issue/Number

6

Publication Date

1-1-2008

Document Type

Article

Language

English

First Page

711

Last Page

717

WOS Identifier

WOS:000257338500008

ISSN

0267-8292

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