Thermotropic and Solution Photoisomerization Properties of Side-Chain Liquid Crystalline Polymers Containing Methyl-Substituted Azobenzene Mesogens
作者:
E. Chiellini,
G. Galli,
A. Altomare,
R. Solaro,
A.S. Angeloni,
M. Laus,
C. Carlini,
D. Caretti,
期刊:
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
(Taylor Available online 1992)
卷期:
Volume 221,
issue 1
页码: 61-69
ISSN:1058-725X
年代: 1992
DOI:10.1080/10587259208037521
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The thermotropic and solution photoisomerization properties of a class of polyacrylates containing differently methyl-substituted azobenzene groups are presented. Methyl-substitution inhibits the tendency to crystallize and causes a dramatic decrease in the stability of the established nematic phases. These effects result from a restriction of the packing capability of the mesogenic groups and a reduction of their length-to-breadth ratio. In dilute solution all polymeric samples undergotrans-to-cisphotoisomerization of the azo group upon irradiation in the absorption region of the π → π* electronic transitions. Photoisomerization rate constants are very similar and of the same order of magnitude as those observed for other polymeric systems containing the unsubstituted azobenzene chromophore.
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