Liquid crystalline behaviour of benzoic acid derivatives containing alkoxyazobenzene

被引：17
作者：
Bai, Binglian [1 ]
Wang, Haitao [1 ]
Xin, Hong [1 ]
Long, Beihong [1 ]
Li, Min [1 ]
机构：
[1] Jilin Univ, Key Lab Automobile Mat, Minist Educ, Inst Mat Sci & Engn, Changchun 130012, Peoples R China
来源：
LIQUID CRYSTALS | 2007年 / 34卷 / 06期
基金：
美国国家科学基金会;
关键词：
D O I：
10.1080/02678290701328118
中图分类号：
O6 [化学];
学科分类号：
0703 ;
摘要：
Liquid crystal trimers based on the hydrogen bonding dimerization of 4-{n-[ 4-( 4-m-alkoxyphenylazo) phenoxy] alkoxy} benzoic acid ( BAm-n) have been synthesized and characterized. Temperature-dependent FTIR spectroscopic studies showed that the carboxylic acid groups in BAm-n are associated to form H-bonded cyclic dimers both in their crystalline and liquid crystalline phases. The trimers exhibited enantiotropic liquid crystalline behaviour except for BA1-3 which showed monotropic behaviour, and the mesophases changed from nematic to smectic phase, with the increase of length of the spacer and the terminal substituents. Pronounced odd-even effects in the melting temperatures, clearing temperatures and nematic-isotropic enthalpy changes were observed.
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页码：659 / 665
页数：7
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