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Dynamics of cholesteric structures in an electric field
O S Tarasov1, A P Krekhov, L Kramer
1Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth, Germany.
Summary
We explain the transverse drift of cholesteric fingers in liquid crystals, revealing that electrohydrodynamic effects drive their rotation and movement under electric fields, similar to Lehmann phenomena.
Area of Science:
- Physics
- Materials Science
- Liquid Crystals
Background:
- Cholesteric liquid crystals exhibit complex behaviors under electric fields.
- Lehmann-like rotation phenomena have been observed in cholesteric drops.
- Understanding the dynamics of cholesteric structures is crucial for materials science applications.
Purpose of the Study:
- To investigate the transverse drift of two types of cholesteric fingers.
- To elucidate the underlying mechanisms responsible for the observed rotation and drift.
- To connect these phenomena to established electrohydrodynamic principles.
Main Methods:
- Studying rotating spiral structures of cholesteric fingers in thin liquid crystal layers.
- Applying alternating current (AC) or direct current (DC) electric fields.
- Analyzing electrohydrodynamic effects, including Carr-Helfrich charge separation and flexoelectric charge generation.
Main Results:
- Demonstrated that electrohydrodynamic effects can accurately describe the transverse drift of cholesteric fingers.
- Identified Carr-Helfrich charge separation and flexoelectric charge generation as key mechanisms.
- Provided a theoretical basis for understanding Lehmann-like phenomena in this context.
Conclusions:
- The transverse drift and rotation of cholesteric fingers are governed by electrohydrodynamic effects.
- These findings offer a unified explanation for observed Lehmann-like phenomena in cholesteric liquid crystals.
- The study advances the understanding of electrokinetics in liquid crystal systems.