Hierarchical structures of self-assembled helical conjugated polymers—Magnetically forced alignment of liquid crystalline poly(meta-phenylene) derivatives

We synthesized poly(meta-phenylene) derivatives with liquid crystalline (LC) groups consisting of phenylcyclohexyl (PCH) or cyanobiphenyl (CB) moiety in the side chains. Thermotropic LC phases and self-assembled structures of the polymers were investigated through polarized optical microscope (POM), differential scanning calorimeter (DSC), and X-ray diffraction (XRD) measurements. The polymers showed discotic liquid crystallinities based on helical structure of the main chains, where the helical chains are self-assembled to form columns along the helical axis. Macroscopic alignments of the polymers were carried out using a magnetic field of 12 T in liquid crystal phases. XRD measurements of the aligned polymers showed that the columns of the main chains are aligned perpendicular to the magnetic field.