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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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Light-Responsive Microstructures in Droplets of the Twist-Bend Nematic Phase
Alexey Eremin1, Hajnalka Nádasi1, Margarita Kurochkina1
1Otto von Guericke University, Institute of Physics , 39016 Magdeburg , Germany.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 26, 2018
Summary
Researchers studied liquid crystal droplets, observing significant changes in elastic properties with temperature. Optical manipulation using UV light altered director structures, offering insights into material behavior.
Area of Science:
- Materials Science
- Soft Matter Physics
- Liquid Crystals
Background:
- Liquid crystals exhibit unique phases like nematic (N) and twist-bend nematic (NTB).
- Elastic constants (K33, K11) govern director configurations in liquid crystals.
- Photoswitchable surfactants enable optical control of liquid crystal properties.
Purpose of the Study:
- Investigate director configurations in liquid-crystalline droplets.
- Analyze the effect of temperature on elastic constants.
- Explore optical manipulation of director structures using UV light.
Main Methods:
- Synthesis and characterization of liquid-crystalline compounds.
- Fabrication of liquid-crystal-in-oil emulsions.
- Polarizing and confocal microscopy for structural and dynamic analysis.
- UV light irradiation for optical manipulation.
Main Results:
- Observed a significant decrease (nearly 2 orders of magnitude) in the K33/K11 ratio with decreasing temperature in the N phase.
- Demonstrated optical manipulation of director structures in doped liquid-crystal droplets.
- Compared findings with conventional 5CB liquid crystal systems.
- Studied droplet dynamics in the NTB phase under UV irradiation.
Conclusions:
- The study reveals strong elastic anisotropy in the investigated liquid crystal.
- Optical control of director configurations is feasible using photoswitchable surfactants.
- Temperature significantly influences the elastic properties of the nematic phase.
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