Synthesis and Characterization of a Novel Liquid Crystalline Star-Shaped Polymer Based on a-CD Core via ATRP

摘要

Well-defined side-chain liquid crystalline star-shaped polymers were synthesized with a combination of the ‘‘core-first’’ method and atom transfer radical polymerization (ATRP). Firstly, the functionalized macroinitiator based on the a-Cyclodextrins (a-CD) bearing functional bromide groups was synthesized, confirmed by 1H-NMR, MALDI-TOF, and FTIR analysis. Secondly, the side-chain liquid crystalline arms poly[6-(4-methoxy-4-oxy-azobenzene) hexyl methacrylate] (PMMAzo) were prepared by ATRP. The characterization of the star polymers were performed with 1H-NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM). It was found that the liquid crystalline behavior of the star polymer a-CD-PMMAzon was similar to that of the linear homopolymer. The phase-transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased as the molecular weight increased for most of these samples. All star-shaped polymers show photoresponsive isomerization under the irradiation with Ultraviolet light.