Effect of terminal polar substituents on the nature of smectic A liquid crystals of a series of 4-(4″-octyloxybenzoyloxy)benzylidene-4′-substituted anilines
作者:
Seiichi Miyajima,
Keisuke Nakazawa,
Keiko Niikura,
Yasuhiro Ujiiye,
Makiko Yashiro,
Takehiko Chiba,
期刊:
Liquid Crystals
(Taylor Available online 1990)
卷期:
Volume 8,
issue 5
页码: 707-718
ISSN:0267-8292
年代: 1990
DOI:10.1080/02678299008047382
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The nature of smectic A liquid crystals and the phase transitions from smectic A to nematic phases are studied in the homologous series of 4-(4″-octyloxy-benzoyloxy)benzylidene-4′-substituted anilines, in which the substituents are H, F, Cl, Br, I, NO2and CN. Measurements have been performed for the dipole moment of the molecule, the smectic A lattice period, the temperatures and the entropies of phase transitions, and the temperature dependence of the orientational order parameter, all of which provide information on the intermolecular pair potentials. It is shown that the introduction of a terminal polar substituent brings about counteracting contributions to the stability of the smectic A state. It is suggested that the reentrant nematic phase transition can appear in the strongly polar mesogens if the extent of antiparallel association of the molecules increases on lowering the temperature.
点击下载:
PDF (607KB)
返 回