Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1‐1‐1 Higashi, Tsukuba, Ibaraki 305‐8565, Japan
Abstract:
An H‐bonded main‐chain liquid‐crystalline (LC) polymer was obtained by in situ photochemical conversion from an H‐bonded LC dimer. A bifunctional compound, 1 , having a cinnamoyl group at one end and a carboxylic acid group at the other, was synthesized as the H‐bonded LC dimer. UV irradiation of 1 in the LC phase in the presence of a sensitizer resulted in its conversion to a photodimer, with a carboxylic acid at both ends, through photocycloaddition of the cinnamoyl moiety. The LC phase was maintained during irradiation, because that of the photodimer was more thermally stable than that of 1 . FT‐IR analysis revealed that the carboxylic acids of the photodimer dominantly formed hydrogen bonds in the LC phase, which suggests that the photodimers assembled into an H‐bonded main‐chain LC polymer.
