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Study of Liquid Crystals Showing Two Isotropic Phases by 1H NMR Diffusometry and 1H NMR Relaxometry.
- Source :
- Crystals (2073-4352); Mar2019, Vol. 9 Issue 3, p178-178, 1p
- Publication Year :
- 2019
-
Abstract
- In this work, we report a study of two thermotropic liquid crystalline samples showing a not common mesophase behavior. The samples, namely a di-benzyloxy biphenyl derivative labelled 9/2 RS/RS, and a bimesogenic liquid crystal labelled L1, show a direct transition between two isotropic phases followed, at lower temperatures, by the optically isotropic, 3D structured, cubic phase. These systems have been investigated by means of <superscript>1</superscript>H NMR diffusometry and <superscript>1</superscript>H NMR relaxometry in order to characterize their isotropic–isotropic'–cubic mesophase behavior, mainly on the dynamic point of view. In particular, the temperature trend of the self-diffusion coefficients measured for both samples allowed us to significantly distinguish between the two isotropic phases, while the temperature dependence of the <superscript>1</superscript>H spin-lattice relaxation time (T<subscript>1</subscript>) did not show significant discontinuities at the isotropic–isotropic' phase transition. A preliminary analysis of the frequency-dependence of <superscript>1</superscript>H T<subscript>1</subscript> at different temperatures gives information about the main motional processes active in the isotropic mesophases. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20734352
- Volume :
- 9
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Crystals (2073-4352)
- Publication Type :
- Academic Journal
- Accession number :
- 135683560
- Full Text :
- https://doi.org/10.3390/cryst9030178