Synthesis and Liquid Crystallinity of Polymethacrylate Systems Containing both Electron-Donating (Quinolinylmethylene)aniline and Electron-Accepting (4'-Nitrobenzylidene)aniline Groups

Abstract

Side-chain liquid-crystalline copolymers, polymer blends, and polymer mixtures containing a (quinolinylmethylene)aniline or a (naphthylmethylene)aniline group and a (4-nitrobenzylidene)aniline group were prepared to examine the effects of the electron-donating character of the quinoline and naphthyl groups on their thermal properties and miscibility. The thermal stability and induction of a smectic phase were caused by the electron donor-acceptor interaction for all copolymers. A miscible polymer blend was obtained from the electron-donating polymer containing the (3-quinolinylmethylene)-aniline group and the electron-accepting polymer containing the (4-nitrobenzylidene)aniline group, while other 1 :1 polymer blends showed phase separation. The 1 :1 miscible polymer blend exhibited a smectic phase from 52 to 166 °C. Moreover, smectic phases were observed in the mixture of the electron-donating polymer containing the mesogenic 3-quinoline group with an electron-accepting low-molecular-weight compound containing the nitrophenyl group as well as in the mixture of both low-molecular-weight compounds containing the above two mesogenic groups. Thus, the (3-quinolinylmethylene)aniline group containing the nitrogen atom acted as the mesogenic electron donor, but not the (naphthylmethylene)-aniline group.