Synthesis and properties of azomethine polymers with bent-core mesogens

Three azomethine polymers with bent-core mesogens in their main chains were synthesized via polycondensation, and the effect of the central bent-core structure (Ar=1,2-phenylene, 2,3-naphthylene, or 2,7-naphthylene) was studied. Although polymers contain bent-shaped mesogens in their main chains, no polymer showed good solubility in common organic solvents but all polymers exhibited liquid crystalline and semi crystalline properties. Two of the three polymers showed thermal degradation before melting due to the high melting point. The polymer with 2,3-naphthylene had a 229°C melting point. The optical texture of the smectic phase could be observed using quenched samples from the melt state. During heating, the smectic layer structure could be detected via X-ray diffraction.