From the Synclinic to the Anticlinic Smectic Phases: a Deuterium NMR and Diffusion NMR Study

ABSTRACT

The behaviour of the ²H NMR line-width throughout the whole mesophasic range of the ferroelectric liquid crystal “1-methylheptyl 4′-(4″-n-decyloxybenzoyloxy) biphenyl-4-carboxylate” (10B1M7) is here reported and discussed.

Static Fringe Field NMR Diffusometry measurements from the isotropic to the anticlinic phase have been performed leading to a significant result concerning the tumbling diffusional coefficient (D_⊥).

These results have been compared to X-Ray measurements and ²H NMR line-widths in order to explain the peculiar behaviour occurring at the transition between the ferroelectric (FLC) and the antiferroelectric (AFLC) liquid crystalline phases.

Keywords:

• diffusion
• dynamics
• ²H NMR
• liquid crystals
• line-width

Acknowledgments

We thank the Italian MIUR for partial financial support. We also thank Prof. B. Zalar and Prof. R. Blinc for helpful discussions and Prof. R. Richardson for the X-Ray contribution.