Short-range smectic order in bent-core nematic liquid crystals

Small angle X-ray diffraction from the uniaxial nematic phase of certain bent-core liquid crystals is shown to be consistent with the presence of molecular clusters possessing short-range tilted smectic (smectic-C) order. Persistence of these clusters throughout the nematic phase, and even into the...

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Published inSoft matter Vol. 6; no. 19; pp. 4819 - 4827
Main Authors Hong, S. H, Verduzco, R, Williams, J. C, Twieg, R. J, DiMasi, E, Pindak, R, Jákli, A, Gleeson, J. T, Sprunt, S
Format Journal Article
LanguageEnglish
Published 01.01.2010
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Summary:Small angle X-ray diffraction from the uniaxial nematic phase of certain bent-core liquid crystals is shown to be consistent with the presence of molecular clusters possessing short-range tilted smectic (smectic-C) order. Persistence of these clusters throughout the nematic phase, and even into the isotropic state, likely accounts for the unusual macroscopic behavior previously reported in bent-core nematics, including an anomalously large flexoelectric effect (∼ 1000 times that of conventional calamitic nematics), very large orientational and flow viscosities (∼ 10-100 and ∼ 100-1000 times, respectively, typical values for calamitics), and an extraordinary flow birefringence observed in the isotropic state. SAXS studies of two bent-core nematic liquid crystals reveal short-range smectic-C layering that persists into the isotropic phase and that could account for remarkable macroscopic properties previously observed in these materials.
ISSN:1744-683X
1744-6848
DOI:10.1039/c000362j