A nematic-polar columnar phase sequence in new bent-shaped liquid crystals based on a 7-hydroxynaphthalene-2-carboxylic acid core

0336595 - FZÚ 2010 RIV GB eng J - Journal Article
Kohout, M. - Svoboda, J. - Novotná, Vladimíra - Pociecha, D. - Glogarová, Milada - Gorecka, E.
A nematic-polar columnar phase sequence in new bent-shaped liquid crystals based on a 7-hydroxynaphthalene-2-carboxylic acid core.
[Posloupnost nematická-sloupcová fáze v nových kapalně-krystalických materiálech na bazi 7-hydroxynaftalenu.]
Journal of Materials Chemistry. Roč. 19, - (2009), s. 3153-3160. ISSN 0959-9428
R&D Projects: GA AV ČR(CZ) GA202/09/0047; GA AV ČR IAA100100710
Institutional research plan: CEZ:AV0Z10100520
Keywords : liquid crystals * bent-shaped mesogen * columnar phase * nematic phase
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 4.795, year: 2009

Mesomorphic properties of new bent-shaped liquid crystals based on 7-hydroxynaphthalene-2-carboxylic acid are presented. The central unit of the molecular core was also modified by substitution of the chlorine atom or methyl group. Texture and calorimetric studies, as well as electrooptical, X-ray and dielectric measurements of selected compounds were performed. For long homologues the lamellar B-2 phase was observed, while for shorter homologues two-dimensional columnar phases were found, built of layer fragments with the electron density modulation plane perpendicular to polarization direction. Based on X-ray patterns, two types of modulated polar columnar phases were distinguished, having oblique or orthogonal centred crystallographic unit cells.

Byly syntetizovány nové kapalně-krystalické látky s molekulami zalomeného tvaru s centrálním naftalenovým jádrem. Byly prostudovány jejich mezomorfní vlastnosti pomocí kalorimetrických, elektro-optických a optických metod a pro většinu látek určeny strukturní parametry vyskytujících se fází (např. rozměry elementární buňky sloupcové fáze).
Permanent Link: http://hdl.handle.net/11104/0005674