Ferroelectric and antiferroelectric liquid crystalline phases in some pyridine carboxylic acid derivatives
作者:N. Kasthuraiah、B. K. Sadashiva、S. Krishnaprasad、Geetha G. Nair
DOI:10.1039/jm9960601619
日期:——
The synthesis and mesomorphic properties of two series of compounds viz.(S)-(+)-4-(1-methylheptyloxy)phenyl 4′-(6″-alkoxypyridine-3-carbonyloxy)benzoates and (S)-(+)-l-methylheptyl4-[4′-(6″-alkoxypyridine-3-carbonyloxy)benzoyloxy]-benzoates are reported; the homologues of the former series exhibit smectic A and smectic C* phases while the derivatives of the latter series show rich polymesomorphism including the antiferroelectric phase. The mesophases have been characterised by using optical polarising microscopy and differential scanning calorimetric methods. Some physical properties such as the spontaneous polarisation, helical pitch, tilt angle and relative permittivity of two derivatives have also been investigated.
Achiral fluorine-containing liquid crystal compounds are provided. The compounds comprise a fluorocarbon terminal portion and a hydrocarbon or another fluorocarbon terminal portion, the terminal portions being connected by a central core, the compounds having smectic mesophases or having latent smectic mesophases. The compounds are useful in liquid crystal display devices both along and in mixtures with other materials. Also provided is a process for preparing these compounds.