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Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
Interlayer self-diffusion and structure of chiral smectic phases studied by 2H NMR exchange experiment
1Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, Canada R3T 2N2.
The Journal of Physical Chemistry. B
|February 14, 2006
Summary
This study uses deuterium 2D exchange NMR to analyze chiral smectic liquid crystals. The research reveals insights into molecular arrangement and self-diffusion in ferrielectric phases, supporting the "asymmetric Clock model".
Area of Science:
- Liquid Crystal Physics
- Materials Science
- Spectroscopy
Background:
- Chiral smectic C (SmC*) liquid crystals exhibit complex chiral subphases.
- Understanding molecular ordering and dynamics in these phases is crucial for their application.
Purpose of the Study:
- To investigate the structure of chiral smectic C (SmC*) and its ferrielectric subphases (SmC*(Fi1), SmC*(Fi2)).
- To demonstrate the utility of deuterium 2D exchange NMR combined with sample rotation for studying molecular dynamics and structure.
Main Methods:
- Deuterium two-dimensional exchange NMR spectroscopy.
- Sample rotation in a magnetic field.
- Analysis of cross-peak intensities in 2D exchange spectra.
Main Results:
- The study successfully measured the translational self-diffusion constant along the helical pitch in the SmC* phase.
- Molecular disposition within the three- and four-layer base units of the SmC*(Fi1) and SmC*(Fi2) phases was elucidated.
- Results provide evidence supporting the 'asymmetric Clock model' for ferrielectric phases.
Conclusions:
- Deuterium 2D exchange NMR with sample rotation is a powerful tool for characterizing liquid crystal phases.
- The 'asymmetric Clock model' effectively describes the ferrielectric phases of the studied smectogen.
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