Thermotropic liquid-crystalline polymers—VI: Comb-like liquid-crystalline polymers of the smectic and nematic types with cyanobiphenyl groups in the side-chains

The syntheses and properties are described for a number of new comb-like liquid-crystalline polyacrylates and polymethacrylates with the same cyanobiphenyl groups in the side-chains but different lengths of the n-aliphatic substituent. The effect of the chemical structure of these polymers on the type of the liquid-crystalline state was examined by means of optical and electron scanning microscopy, X-ray and DSC methods. The polyacrylates with short n-aliphatic chains form the nematic mesophase, the polyacrylates with long n-aliphatic substituents and polymethacrylates form the smectic mesophase. The dependence of thermal properties of the nematic and smectic polymers upon their intrinsic viscosities is established.