Comb-shaped liquid-crystalline ionogenic copolymers

A series of new ionogenic liquid-crystalline copolymers were synthesized by radical copolymerization of 1,4-(4-cyanobiphenyloxy)butyloxycarbonylethylene with acrylic acid. The presence of acrylic acid units did not prevent the formation of a nematic phase characteristic of the starting cyanobiphenyl homopolymer. At the content of acrylic acid ranging from 42 to 52 mol %, the copolymers formed a S-A mesophase. This is associated with an increase in the rigidity of the backbone chain due to the formation of intramolecular hydrogen bonds. An increase in the concentration of acrylic acid above 55% hampers-the formation of the mesophase, and the resulting copolymers become amorphous. The decisive role of the intramolecular hydrogen bonds in inducing S-A phase was confirmed by the synthesis and investigation df the copolymers with the same mesogenic group, but differing by the second component (methyl acrylate was used as the second component); these copolymers only formed nematic phase. The blends of ionogenic LC copolymers with a low-molecular-mass surfactant were studied. The process of the reorientation of ionogenic LC copolymers in a magnetic field was studied by broad-band H-1 NMR spectroscopy, and the temperature dependences of the order parameter S were determined.