Paranematic–nematic phase transition in liquid crystalline elastomers: a ²H-NMR study

Abstract

In this study, selectively deuterium-labelled monodomain liquid single crystalline elastomers have been investigated by means of ²H-NMR spectroscopy. The analysis of the spectral features as well as the study of the orientational properties in the paranematic and nematic phases confirmed the supercriticality of the paranematic–nematic transition as an intrinsic property of these systems. Moreover, the combined study of the spin–spin relaxation times (T ₂) and the ²H-NMR spectral linewidth measured in the paranematic phase indicates the presence of slow dynamic motions.

Keywords:

• shape memory
• actuators
• orientational order
• dynamics
• liquid crystal elastomers

Acknowledgement

V. Domenici and B. Zalar are grateful to the Marie Curie Intra-European Fellowship project (no. 039643 ‘ELACEM’) for providing partial funding to this study.