Asymmetry in molecular ordering in the nematic phase: DMR study

Wu, Bao-Gang; Ziemnicka, Barbara; Doane, J. William
January 1988
Journal of Chemical Physics;1/15/1988, Vol. 88 Issue 2, p1373
Academic Journal
Deuterium nuclear magnetic resonance (2H-NMR) was performed on the rigid perdeuterated fluorene segment of the compound 2-fluorenyl-4’-tetradecyloxy benzoate (FLOC 14-d9) to unambiguously measure the order parameter U which reflects the degree of asymmetric ordering of the molecule in the nematic liquid crystalline phase. Measurements of U showed this parameter to be finite at all temperatures in the nematic phase indicative of the uniaxial phase U2 described in the Allender–Lee generalized Landau theory. Mixtures of FLOC 14-d9 with compounds consisting of molecules more cylindrical in shape were also studied to examine their effect on the parameter U. Other parameters such as the degree of order S and the orientation of the principal axes of the Maier–Saupe order matrix were measured and are discussed.


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