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The influence of an alkenyl terminal group on the mesomorphic behavior and electro-optic properties of fluorinated terphenyl liquid crystals

Hird, Mike; Lewis, Robert

Authors

Mike Hird M.Hird@hull.ac.uk

Robert Lewis R.A.Lewis@hull.ac.uk



Abstract

Novel liquid crystal terphenyls with two, three and four lateral fluoro substituents and an alkene unit at the end of a terminal chain are presented in terms of synthesis, mesomorphic behaviour and electro-optic properties. The difluoro analogues were found to exhibit the smectic C phase over a wide temperature range, with short temperature ranges of the smectic A and the nematic phase above. Very low melting points were recorded for the trifluoro analogues, and the shorter chain homologues of these materials exhibit the nematic phase over a wide temperatures with a monotropic smectic C phase and the higher homologues exhibit the smectic C phase over a wide temperature range with the nematic phase above. The tetrafluoroterphenyls exhibit the nematic phase over a wide temperature range with the complete absence of smectic phases. As appropriate, the materials were evaluated for dielectric anisotropy and threshold voltage in nematic phase, and mixed with a chiral dopant to evaluate the spontaneous polarisation, tilt angle and switching times in the chiral smectic C phase. The results show that these compounds are strong potential candidates for application in both vertically aligned nematic (VAN) and ferroelectric liquid crystal (FLC) devices.

Journal Article Type Article
Publication Date Jan 1, 2010
Journal Journal of Materials Chemistry
Print ISSN 0959-9428
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 20
Issue 2
Pages 299 - 307
APA6 Citation Hird, M., & Lewis, R. (2010). The influence of an alkenyl terminal group on the mesomorphic behavior and electro-optic properties of fluorinated terphenyl liquid crystals. Journal of materials chemistry, 20(2), 299 - 307. doi:10.1039/b914260f
DOI https://doi.org/10.1039/b914260f
Keywords alkylalkenyloxyfluoroterphenyl liq crystal nematic dielec anisotropy threshold voltage switching
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