Dimerization behavior of cinnamate group attached to flexible polymer backbone and its effect on the molecular orientation

Cinnamate group is well-known for the dimerization reaction by ultraviolet irradiation and their anisotropic dimerization are used for aligning liquid crystals. In this work, we found that cinnamate groups attached to the flexible polymer backbone could be reacted by thermal energy as well as UV irradiation. Cinnamate group of flexible polymers shows different molecular orientation of cycloadducts, comparing with conventional polymers, and it also participates in insolubilization reaction by additional thermal treatment. The thermal insolubilization reaction of flexible cinnamate polymer might be appropriate for the enhancement of molecular orientation.