Fast switching near a smectic-to-nematic phase transition

    Authors

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

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    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

    Share

    COinS