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A. M. Parshin^1,2, V. A. Gunyakov^1,2, V. Ya. Zyryanov^1,3, V. F. Shabanov^1,3

Author affiliations
¹Kirensky Institute of Physics, Krasnoyarsk Scientific Centre, SB RAS
Krasnoyarsk 660036, Akademgorodok 50, Russia. 
E-mail: gun@iph.krasn.ru
²Siberian Federal University,
Krasnoyarsk 660041, 79 Svobodny prospect, Russia
³Siberian State Aerospace University
Krasnoyarsk, 660014, 31 Krasnoyarsky rabochy prospect, Russia

Abstract
The interaction of a 4-n-pentyl-4'-cyanobiphenyl nematic liquid crystal with a polyvinyl butyral surface, cured with phase separation under magnetic field was investigated. From the measurement of polarized components of optical transmission of nematic matrix doped by dichroic dye the azimuthal cohesion energy of liquid crystal with polymer surface was obtained. From the threshold field of the Freedericksz transition the polar cohesion energy was found. This parameter is at least twice higher than the azimuthal one. The analysis of molecular interaction liquid crystal – polymer showed that azimuthal cohesion of nematics is due to the short-range inductive polar forces while the long-range dispersive forces are responsible for their polar cohesion with the polymer surface.

Keywords: nematic liquid crystal, polymer film, cohesion energy, Freedericksz transition, magnetic field