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Updated: Jul 3, 2026
07:03
Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
Effects of doping on an unusual smectic- C*alpha-smectic-C*FI2-smectic-C* phase sequence
1School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA and Department of Mathematics and Physics, Azusa Pacific University, Azusa, California 91702, USA.
Summary
The liquid crystal 10OHF exhibits a unique inverted phase sequence. This unusual smectic-C*FI2 phase stabilizes in mixtures, demonstrating a novel liquid crystal behavior.
Area of Science:
- Liquid crystal physics
- Materials science
- Phase transitions
Background:
- The homologous series of nOHF compounds are liquid crystals.
- 10OHF displays a unique, partially inverted phase sequence where the smectic-C*FI2 phase appears at a higher temperature than the smectic-C* phase.
- This inverted phase sequence is unprecedented among known liquid crystals.
Purpose of the Study:
- To identify and characterize the phase sequences of 9OHF, 10OHF, 11OHF, and 12OHF using ellipsometry.
- To investigate the phase behavior of 10OHF when mixed with a standard liquid crystal (C11).
- To explore the influence of surface interactions on phase transitions in thin films of these mixtures.
Main Methods:
- Ellipsometry was employed to determine the phase sequences of individual compounds (9OHF, 10OHF, 11OHF, 12OHF).
- Binary mixtures of 10OHF and C11 were prepared and analyzed.
- Phase diagrams of the mixtures were studied to observe phase stability and predominance.
- Thin films of selected mixtures were examined for surface-induced reentrant phase transitions.
Main Results:
- The phase sequences of 9OHF, 10OHF, 11OHF, and 12OHF were successfully identified.
- Binary mixtures of 10OHF with C11 exhibited stabilization of the unusual phase sequence, with the smectic-C*FI2 phase dominating over the smectic-C* phase across the entire mixing diagram.
- In thin films, surface interactions were observed to induce a reentrant transition sequence (smectic-C*FI2-smectic-C*-smectic-C*FI2).
Conclusions:
- 10OHF possesses a unique, partially inverted phase sequence, distinguishing it from its homologs and other liquid crystals.
- The unusual phase sequence of 10OHF is stabilized and predominates in binary mixtures with C11.
- Surface interactions can induce complex reentrant phase behavior in thin films of these liquid crystal mixtures.
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