Study of liquid crystals showing two isotropic phases by 1 H NMR diffusometry and 1 H NMR relaxometry

Anton Gradišek, Mario Cifelli, Michal Wojcik, Tomaž Apih, Sergey V. Dvinskikh, Ewa Gorecka, Valentina Domenici

Research output

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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 1 H NMR diffusometry and 1 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 1 H spin-lattice relaxation time (T 1 ) did not show significant discontinuities at the isotropic–isotropic’ phase transition. A preliminary analysis of the frequency-dependence of 1 H T 1 at different temperatures gives information about the main motional processes active in the isotropic mesophases.

Original languageEnglish
Article number178
Number of pages16
JournalCrystals
Volume9
Issue number3
DOIs
Publication statusPublished - Mar 2019

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Scopus subject areas

  • Condensed Matter Physics
  • Chemical Engineering(all)
  • Materials Science(all)
  • Inorganic Chemistry

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