Abstract
This paper describes an experimental investigation of dipole-dipole interactions between molecules in an orientational ordered environment. Measurements are reported of the dielectric properties of a series of anisotropic solutions of two structurally similar dipolar solutes 1-cyano-2-fluoro-4-[trans-4-(trans-4-propylcyclohexy) cyclohexyl]benzene (CP1) and 1,2-difluoro-4-[trans-4-(trans-4-propylcyclohexy)cyclohexyl]benzene (CP3) dissolved in a in a non-polar liquid crystal solvent 1-ethyl-3-fluoro-4-trans-4-ethylbiphenylethane (I22). The results indicate that the dipolar interactions in CP1 solutions are qualitatively different from those for CP3 solutions. In particular the dielectric properties of CP1 solutions can be interpreted by assuming that solute molecules are locally ordered antiferroelectrically, while for CP3 solutions the local order appears to be ferroelectric. The results can be fitted to an association model that enables the proportion of parallel and anti-parallel species to be determined.
