화학공학소재연구정보센터
Macromolecules, Vol.48, No.4, 908-914, 2015
Photoalignable Radical Initiator for Anisotropic Polymerization in Liquid Crystalline Media
A rod-shaped azobenzene derivative possessing a 2-benzoyl-2-propanol moiety (Az-PIni) was synthesized. This molecule was highly compatible with calamitic nematic liquid crystal (LC) systems and showed dual photofunctions as a photocommander for the alignment of LCs upon linearly polarized light (LPL) irradiation and a photoinitiator for the radical polymerization in these media. The dual photofunctions were achieved simultaneously by irradiation with 365 nm LPL, or stepwisely with 436 nm LPL for the photoalignment, and successively with 254 nm light for the photoinitiated polymerization. In a nematic LC cell, these combined processes provided a persistent uniform alignment. When a polymerizable LC monomer film was coated on an elastomeric sheet, the anisotropic photopolymerization of the photoaligned monomer initiated by Az-PIni led to a uniformly aligned wrinkle formation via polymerization shrinkage.