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Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
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Local structural ordering in surface-confined liquid crystals
I Śliwa1, W Jeżewski1, A V Zakharov2
1Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland.
The Journal of Chemical Physics
|July 3, 2017
Summary
Confining surfaces induce complex ordering in liquid crystals, with smectic layers forming near surfaces even as bulk phases change. Surface interactions influence phase transitions but do not prevent melting near boundaries.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Physical Chemistry
Background:
- Liquid crystals exhibit complex phases like smectic A, nematic, and isotropic.
- Surface interactions significantly influence molecular ordering in confined systems.
- Understanding these interactions is crucial for designing advanced materials.
Purpose of the Study:
- Investigate the effects of nonlocal surface interactions and intermolecular couplings on liquid crystal structures in thin cells.
- Analyze the interplay between surface forces and bulk phase behavior.
- Explore the formation and behavior of phase interfaces under confinement.
Main Methods:
- Extended McMillan mean field theory for finite systems.
- Analysis of molecular ordering (orientational and translational) under confinement.
- Thermodynamic modeling of phase transitions and interfaces.
Main Results:
- Confining surfaces induce complex orientational and translational ordering.
- Smectic A, nematic, and isotropic phases can coexist within finite cells.
- Surface freezing of smectic layers observed even with weak surface interactions.
- Melting of surface layers occurs near boundaries, distinct from bulk behavior.
- Internal interfaces form fronts of local finite-size transitions driven by temperature.
Conclusions:
- Surface interactions play a critical role in dictating liquid crystal phase behavior in confined geometries.
- The degree of molecular packing strongly influences the thermal properties and transition behaviors.
- Complex phase coexistence and surface phenomena are inherent to thin-film liquid crystal systems.
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