Mesogen conformation changes in thermotropic polyesters at phase transitions

✍ Scribed by Sergei Shilov; Boris Volchek; Vyacheslav Zuev; Sergei Skorokhodov

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 439 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950305

✦ Synopsis

Abstract

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.