MOLECULAR DYNAMICS AND DIPOLAR AGGREGATION IN SOME FLUORO-SUBSTITUTED LIQUID CRYSTALS

摘要

The article presents the results of the molecular dynamics and dipolar aggregation studies performed with the use of dielectric spectroscopy for two differently fluoro-subslituted nematogenic compounds: 4-cyano-3-fluorophenyl 4'-n-octyloxybenzoate [C_8H_(17)OPhCOOPh(F)CN] and 4-cyanophenyl 4'-n-octyloxy-3'-fluorobenzoate [C_8H_17OPh(F)COOPhCN]. The dielectric relaxation spectra recorded in the isotropic and nematic phases of the compounds as well as the activation energies corresponding to the molecular rotation around the short axis and the conductivity are analyzed. The role of the molecular structure in the aggregation ability of the compounds is discussed in relation to the dielectric anisotropy, the most important property of the nematic liquid crystals exploiting in opto-electronic devices.