Nitroxide-mediated `living' free radical synthesis of novel rod-coil diblock copolymers with polystyrene and mesogen-jacketed liquid-crystal polymer segments

The synthesis of rod-coil diblock copolymers with narrow polydispersity was achieved for the first time by TEMPO-mediated `living' free radical polymerization of styrene and 2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene. The block architecture of the two diblock copolymers thus prepared, MPCS-block-St (5400/2400) and MPCS-block-St (10 800/8700), was confirmed by GPC, 1H and 13C NMR and DSC studies. The liquid-crystalline behaviour of the copolymers was studied by DSC and polarized optical microscope. It was observed that both copolymers showed two distinct glass transitions, corresponding to polystyrene and poly(-2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene). Above the glass transition temperature of rigid block, liquid-crystalline phase was formed. The clearing point of the phase is higher than the polymer decomposition temperature.EI03243-2474