A New Association Model for Nematogenic Systems—Its Significance for Liquid Crystal Materials Research

Abstract

Abstract The importance of molecular association is considered in relation to the physical properties of a number of nematogens. It is proposed that association leads to the formation of polar and apolar dimers, which influence the dielectric and electro-optic properties of nematic liquid crystals. Dielectric and light scattering measurements of polar and apolar correlation factors are reported for a series of dipolar mesogens, and interpreted in terms of a model for molecular association. Both the solute molecular structure and nature of the solvent influence the degree of association, and the good device properties of mixtures of positive and negative nematogens is tentatively attributed to the strong tendency of dipolar solutes to associate in negative nematic solvents.