Cybotactic nematic phase in main-chain polyesters with bent-core mesogens

New six main-chain polyesters containing bent-core mesogens with various central units (Ar = 1,2- or 1,3-phenylene and 1,6-, 1,7-, 2,3- or 2,7-naphthylene) were synthesized. All of the polymers were soluble in a mixture of phenol/p-chlorophenol/TCE (25/40/35 w/w/w). The inherent viscosities were in the range of 0.18–0.38 dL/g. Despite the existence of bent-core mesogens eliciting a remarkable diminution of molecular packing, polymer with Ar = 2,7-naphthylene formed a smectic phase, and polymers with both Ar = 1,2-phenylene and 2,3-naphthylene formed nematic phases. Moreover, most of the polymers were distinctly semi-crystalline. Herein, we report our findings regarding the first detection of cybotactic groups from the nematic phases of main-chain polyesters with bent-core mesogens.