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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.

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. https://doi.org/10.1039/b914260f

Journal Article Type Article
Acceptance Date Jan 1, 2010
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
DOI https://doi.org/10.1039/b914260f
Keywords alkylalkenyloxyfluoroterphenyl liq crystal nematic dielec anisotropy threshold voltage switching
Public URL https://hull-repository.worktribe.com/output/418041