Unusual Orientational Behavior of Anthraquinone Dyes in Nematic Cyanophenylcyclohexane Derivatives

Abstract

The optical order parameters of a number of anthraquinone and azo dyes are determined in three nematic liquid crystalline hosts. The results are discussed in terms of the effects of the hosts on the dye order parameters. It is found that the anthraquinone dyes show significantly higher order parameters in the host composed of cyanophenylcyclohexane derivatives. This enhancement of the orientational ordering is tentatively interpreted as being due to the supplement of the orientational cohesive forces with the charge-transfer interaction between the dyes and the host.