Synthesis of a side chain liquid crystalline polycarbonate with a chiral backbone

Official URL: http://dx.doi.org/10.1002/app.24298

We report the experimental demonstration of a novel and environmentally benign supercritical carbon dioxide (ScCO2) technique that yields an optically active, side chain liquid crystalline polycarbonate in a single-step reaction. The obtained polymer is worthwhile, since it is highly stereoregular and can find applications in an enlarged mesomorphic temperature range compared to its acrylic analogues. The synthesized materials were characterized by IR, 1H-NMR, and 13C-NMR, while the thermal properties were measured by DSC. Polarized optical micrograph and wide angle X-ray diffraction were used for the mesogenic property characterization of the copolymer. The transfer chirality from the backbone to the mesophase is demonstrated on the optical microscopy textures. Being consistent with the 13C-NMR, X-ray implies an ordered polymeric structure. The DSC analysis of the copolymer indicates that the Ti (the clearing point temperature) value does not change dramatically, whereas a pronounced decrease in Tg (the glass transition temperature) value is observed from that of its acrylic analogues. Hence, the obtained polymer exhibits another practical benefit by widening the mesomorphic temperature range. This study is the insightful combination of material processing and chemical design that elucidates the advantages of ScCO2 application, in terms of liquid crystallinity and the tacticity of the obtained polymer.