The synthesis of liquid crystalline copolymers with block copolymer grafts

The synthesis of novel copolymers consisting of a side-group liquid crystalline backbone and poly(tetrahydrofuran)-poly(methyl methacrylate) block copolymer grafts was realized by using cationic-to-free-radical transformation reactions. Firstly, photoactive poly(tetrahydrofuran) macroinimers were prepared by cationic polymerization of tetrahydrofuran and subsequent termination with 2-picoline N-oxide. Secondly, the macroinimers and acrylate monomers containing different spaced cyanobiphenyl mesogenic groups were copolymerized to yield the respective graft copolymers. Eventually, these were used for indirect photochemical polymerization of methyl methacrylate by UV irradiation in the presence of anthracene as a photosensitizer leading to the final copolymers with block copolymer grafts. The liquid crystalline, semicrystalline, and amorphous blocks were micro-phase separated in the graft copolymers.