Thermotropic ionic liquid crystals. V. Deuterium NMR study of sodium n-alkanoates

M. L. Phillips, Thomas Barbara, S. Plesko, J. Jonas

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Deuterium NMR spectra and spin-lattice relaxation times T1 were obtained as functions of temperature for α-deuterated sodium n-alkanoates (nc = 4-7) in the smectic A and "isotropic" liquid phases. The temperature dependence of the orientational order parameter is found to disagree with the predictions of McMillan's and Woo's theories for the smectic A phase. Reorientational models are presented to explain the experimental order parameters in terms of the structure of the anhydrous solid or the lyotropic gel phase of these compounds. The same models are used in the analysis of reorientational contributions to the 2D T1 in the mesophase; order director fluctuations are also estimated to contribute significantly to the relaxation times. The 2D T1 temperature dependence in the mesophase resembles that of the 23Na T1 measured previously, implying shared relaxation mechanisms for the two nuclei. Estimated correlation times for 2D relaxation in the isotropic phase provide evidence for the persistence of local structure characterized by motion on a time scale of tens of picoseconds.

Original languageEnglish (US)
Pages (from-to)5143-5151
Number of pages9
JournalThe Journal of Chemical Physics
Volume84
Issue number9
StatePublished - 1986
Externally publishedYes

Fingerprint

Ionic Liquids
Liquid Crystals
Deuterium
ionic crystals
deuterium
relaxation time
Sodium
liquid crystals
Nuclear magnetic resonance
sodium
Relaxation time
temperature dependence
nuclear magnetic resonance
spin-lattice relaxation
liquid phases
Spin-lattice relaxation
gels
Temperature
nuclei
predictions

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Thermotropic ionic liquid crystals. V. Deuterium NMR study of sodium n-alkanoates. / Phillips, M. L.; Barbara, Thomas; Plesko, S.; Jonas, J.

In: The Journal of Chemical Physics, Vol. 84, No. 9, 1986, p. 5143-5151.

Research output: Contribution to journalArticle

Phillips, M. L. ; Barbara, Thomas ; Plesko, S. ; Jonas, J. / Thermotropic ionic liquid crystals. V. Deuterium NMR study of sodium n-alkanoates. In: The Journal of Chemical Physics. 1986 ; Vol. 84, No. 9. pp. 5143-5151.
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