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Mesogen conformation changes in thermotropic polyesters at phase transitions
Author(s) -
Shilov Sergei,
Volchek Boris,
Zuev Vyacheslav,
Skorokhodov Sergei
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950305
Subject(s) - mesogen , thermotropic crystal , polyester , liquid crystal , polymer chemistry , methylene , polymer , phase (matter) , crystallography , chemistry , materials science , liquid crystalline , organic chemistry , optoelectronics
Mesogen conformations in thermotropic polyesters with alternating mesogens and poly(methylene) spacers were investigated by IR spectroscopy with polarized and unpolarized light. The selective deuteration of terephthaloyl‐bis( p ‐oxybenzoate) mesogens gave a possibility of assigning part of the IR bands to terephthalic or to oxybenzoic fragments. It is shown that in the liquid crystalline melt the mesogen conformation is planar, but in the semicrystalline state it is mainly nonplanar. Differences in mesogen conformations of polymers containing an even or an odd number of methylene units in the spacer are detected. Thus, LC ordering seems to affect not only the conformation of the spacer but also the conformation of the mesogen.