Synthesis and characterization of side chain polymer with helical PLLA segments containing mesogenic end group

Series of mesogenic biphenol derivatives HO6OPPOn (n = 4,6,8) were prepared by asymmetric reaction and purified. Then HOLAxO6OPPOn were prepared with controlled molecular weights by adjusting the feed ratios of HO6OPPOn, SnOct2 catalyst and LLA by Ring-Opening Polymerization. P-AOLAxO6OPPOn materials were obtained in high yields by the free radical polymerization of polymerizable macromonomers of AOLAxO6OPPOn synthesized by esterization of HOLAxO6OPPOn with acrylic acid in the presence of DCC/DMAP. Their molecular weights were characterized by 1H NMR and GPC. Differential Scanning Calorimeter method and Polarized Optical Microscopy method were used to study their thermal behaviors. Both AOLAxO6OPPOn and P-AOLAxO6OPPOn materials are found to form LCs with increased Tg, Tm and Ti with longer O-LLA segment length. Polymerization of AOLAxO6OPPOn also resulted in the increase of Tg, Tm and Ti. X-ray diffraction measurements revealed the presence of smectic phase in these materials. The O-LLA segments are in helical structure from CD spectra and this makes the resulting polymer materials good candidate of optical materials for huge optical rotation power.

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