A Pulsed NMR Study of Transient and Persistent Molecular Order in Nematic Liquid Crystals

  • P. A. Mitchel
  • C. E. Tarr


The proton absorption spectrum of a typical nematic liquid crystal shows one or more well separated pairs of lines arising from the large dipolar interaction of protons on the phenyl rings. Because these interactions have cylindrical symmetry with respect to the nematic director, observation of the splittings gives a direct measure of the orientation of the director with respect to the magnetic field. Experiments are reported in which pulsed NMR techniques were used to determine persistent molecular order and orientation in response to applied electric fields. From these experiments it was possible to determine the temperature dependence of the flow alignment angle for PAA. These data show the first evidence of flow alignment in the super-cooled nematic state. In addition studies of CBEOA yielded information about the time evolution of molecular order and orientation in response to the sudden application of an electric field.


Nematic Liquid Crystal Dielectric Anisotropy Nematic Director Nematic Order Parameter Sudden Application 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    E. F. Carr, Adv. in Chem. Ser. 63, 76 (1967).CrossRefGoogle Scholar
  2. 2.
    W. Helfrich, J. Chem. Phys. 51, 4092 (1969).CrossRefGoogle Scholar
  3. 3.
    D. P. McLemore, Ph.D. Thesis, Univ. of Maine, 1973 (unpublished).Google Scholar
  4. 4.
    T. E. Kubaska, C. E. Tarr, Mol. Cryst. Liq. Cryst. 29, 155 (1974).CrossRefGoogle Scholar
  5. 5.
    C. E. Tarr, E. F. Carr, Solid State Commun. 33, 459 (1980).CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1984

Authors and Affiliations

  • P. A. Mitchel
    • 1
  • C. E. Tarr
    • 1
  1. 1.Department of Physics and AstronomyUniversity of Maine at OronoOronoUSA

Personalised recommendations