Liquid-crystalline phase transition in organophosphazenes

✍ Scribed by Keiichi Moriya; Toshiya Suzuki; Yasuyuki Kawanishi; Tsuyoshi Masuda; Hiroshi Mizusaki; Shigekazu Nakagawa; Hiroshi Ikematsu; Katsuyuki Mizuno; Shinichi Yano; Meisetsu Kajiwara

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 146 KB
• Volume: 12
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(199810/11)12:10/11<771::aid-aoc785>3.0.co;2-e

✦ Synopsis

Organophosphazenes with a similar mesogenic moiety were prepared and their mesogenicity was studied by differential scanning calorinetry (DSC) measurements and polarizing microsope observations. In cyclotriphosphazenes with alkoxybiphenyl and Schiff base moieties, mesomorphic phase transitions were observed, but no mesomorphic phase was observed for the corresponding cyclotetraphosphazenes. In polyphosphazenes with an alkoxybiphenyl moiety, no mesomorphic phase was observed. The molecular structure of cyclotriphosphazenes facilitated the formation of a mesomorphic layer structure; in contrast, the formation of a mesomorphic layer structure did not occur in cyclotetraphosphazenes and polyphosphazenes, even though they bore a similar mesogenic moiety. Moreover, in cyclotriphosphazenes with an optically active alkoxybiphenyl group, a smectic C * phase was observed. The spontaneous polarization of the compound was À190 m C m À2 at 436 K in 25 m in cell using the triangular-wave method. # 1998 John Wiley & Sons, Ltd.