Physical Chemistry Chemical Physics · 2017 · 317 citations · 20 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsPhase TransformationsPhysical ChemistryCrystallization ProcessesCrystallographyLiquid Crystal MaterialsLiquid CrystalsPhase ChangePhase TransitionsDielectric ConstantDielectric FunctionLiquid Crystal Dielectric PropertiesLiquid Crystal Phase TransitionsMesophase StructurePhase Transition TemperatureScattering ExperimentsSmectic Phases
). When studied by microscopy and X-ray scattering experiments, and under applied electric fields, the nematic phases are practically identical. However, calorimetry experiments refute the possibility of an intervening smectic mesophase, and the transformation between the nematic phases was associated with a weak thermal event. Analysis of measured dielectric data, along with molecular properties obtained from DFT calculations, applying the Maier-Meier relationship allowed for the degree of antiparallel pairing of dipoles in both nematic phases to be quantified. Based on the results, we conclude that the onset of the lower temperature phase is driven by the formation of antiparallel molecular associations.
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Electric Moments of Molecules in Liquids
Lars Onsager · Journal of the American Chemical Society · 1936 · 5.3K citations
Thermotropic Biaxial Nematic Liquid Crystals
Louis A. Madsen, Theo J. Dingemans, Michi Nakata et al. · Physical Review Letters · 2004 · 590 citations