Synthesis of mesogen-jacketed liquid crystalline polymers with long symmetry mesogenic core containing two biphenyls

A series of mesogen-jacketed liquid crystalline polymers, poly {2,5-bis[(4-alkoxybiphenyl)oxycarbonyl]-styrenes} (P-Cm, m = 8, 10, 12, 14 and 18) were designed and successfully synthesized via free radical polymerization. The chemical structures of the monomers were confirmed by 1H NMR, 13C NMR and Mass Spectrometry. The molecular characterizations of the polymers were performed with 1H NMR, GPC and TGA. The phase structures and transitions of the polymers were investigated by the combination of techniques including DSC, POM, temperature-variable FT-IR spectroscopy, 1D WAXD and SAXS. The experimental results suggest that the polymers with symmetry mesogenic core containing two biphenyls can develop into a well-defined smectic A (SA) phase. This implies that MJLCPs molecules shape can be modulated from rod-like to ribbon-like by simply changing the length of the mesogenic group.