Molecular Crystals and Liquid Crystals, Vol.529, 10-19, 2010
Photoinduced Orientation of Liquid Crystalline Copolymer Films with Cinnamic Acid Side Groups Synthesized by RAFT Polymerization
Liquid crystalline (LC) polymethacrylates with hexamethylene spacer groups terminated with photoreactive hydrogen (H) bonded 4-oxycinnamic acid (CA) in the side chain were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The influence of the molecular weight on the thermal property, photoreactivity, and thermally enhanced photoinduced molecular reorientation behavior was investigated. All polymers exhibited a nematic LC phase, and thermally enhanced photoinduced in-plane molecular reorientation was achieved by irradiating with linearly polarized UV light and subsequent annealing. The molecular weight did not affect the photoreactivity and the axis-selectivity of anisotropic photoreaction of thin films, but effective annealing temperature and the maximum thermally enhanced in-plane order decreased as the molecular weight of the polymer decreased.