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Updated: May 7, 2026
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High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
Shape and chirality transitions in off-axis twist nematic elastomer ribbons
Yoshiki Sawa1, Kenji Urayama, Toshikazu Takigawa
1Department of Material Chemistry, Kyoto University, Kyoto 615-8510, Japan.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 17, 2013
Summary
Nematic elastomer ribbons twist into complex shapes like helicoids and spirals. Their shape and chirality change with temperature and director orientation, offering insights for material design.
Area of Science:
- Materials Science
- Soft Matter Physics
- Polymer Chemistry
Background:
- Nematic elastomers exhibit unique shape-morphing properties due to their liquid crystal alignment.
- Understanding director orientation is crucial for predicting elastomer behavior.
- Twisted nematic elastomers offer tunable mechanical responses.
Purpose of the Study:
- To investigate the temperature-dependent shape evolution of off-axis twist nematic elastomer ribbons.
- To correlate director orientation at the sample midplane with observed shapes.
- To explore the mechanisms behind macroscopic chirality transitions.
Main Methods:
- Experimental characterization of elastomer ribbon shape changes.
- Finite element simulations to model shape evolution.
- Analysis of director orientation and its impact on morphology.
Main Results:
- Ribbons form helicoids or spirals when the midplane director is aligned with ribbon axes.
- Off-axis director orientations lead to distorted spiral shapes, not helicoids.
- All samples exhibited a temperature-induced transition from right- to left-handed chirality.
- Simulations predicted temperature-independent chirality changes in off-axis samples based on angular offset.
Conclusions:
- Shape evolution and macroscopic chirality are highly sensitive to director orientation.
- The study provides a mechanistic understanding of shape transitions in nematic elastomers.
- Findings enable the engineering design of nematic elastomers for specific applications.
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