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Effect of terminal polar substituents on the nature of smectic A liquid crystals of a series of 4-(4''-octyloxybenzoyloxy)benzylidene-4'-substituted anilines

Authors :
Miyajima, Seiichi
Nakazawa, Keisuke
Niikura, Keiko
Ujiiye, Yasuhiro
Yashiro, Makiko
Chiba, Takehiko
Source :
Liquid Crystals; November 1990, Vol. 8 Issue: 5 p707-718, 12p
Publication Year :
1990

Abstract

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, NO2 and 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.

Details

Language :
English
ISSN :
02678292 and 13665855
Volume :
8
Issue :
5
Database :
Supplemental Index
Journal :
Liquid Crystals
Publication Type :
Periodical
Accession number :
ejs11409697
Full Text :
https://doi.org/10.1080/02678299008047382