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High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
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Patterns driven by combined ac and dc electric fields in nematic liquid crystals.
Alexei Krekhov1, Werner Decker2, Werner Pesch2
1Max Planck Institute for Dynamics and Self-Organization, D-37077 Göttingen, Germany.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|October 30, 2014
Summary
Superimposed AC and DC electric fields influence electroconvection and flexoelectric patterns in nematic liquid crystals. Combined fields can enhance or suppress pattern formation, with experimental results largely confirming theoretical predictions.
Area of Science:
- Physics
- Materials Science
Background:
- Nematic liquid crystals exhibit complex electrohydrodynamic behaviors.
- Electric fields are known to induce pattern formation in liquid crystals.
Purpose of the Study:
- To investigate the effect of superimposed alternating current (AC) and direct current (DC) electric fields on electroconvection and flexoelectric patterns.
- To characterize pattern formation in the parameter space of AC and DC field magnitudes.
Main Methods:
- Utilized an extended standard model for electrohydrodynamic instabilities.
- Performed numerical and approximate analytical calculations.
- Conducted experimental validation of theoretical predictions.
Main Results:
- The combined action of AC and DC electric fields can either enhance or suppress pattern formation.
- The influence of combined fields depends on the type of patterns and AC frequency.
- Theoretical predictions were qualitatively confirmed by experimental observations in most cases.
Conclusions:
- The interplay between AC and DC electric fields significantly modulates pattern formation in nematic liquid crystals.
- Discrepancies between theory and experiment suggest the need for further theoretical refinement.
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