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Updated: Jan 1, 2026
06:24
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
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High-contrast and reversible polymer thermal regulator by structural phase transition.
Ramesh Shrestha1, Yuxuan Luan1, Sunmi Shin2
1Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Science Advances
|December 20, 2019
Summary
Researchers developed a novel polymer thermal regulator using crystalline polyethylene nanofibers. This material exhibits a high-contrast, reversible thermal switching ratio of ~10x, surpassing existing solid-state materials.
Area of Science:
- Materials Science
- Solid-State Physics
- Polymer Science
Background:
- Active control of heat flow using solid-state thermal components remains underdeveloped compared to electronic counterparts.
- Developing switchable thermal materials is crucial for advanced thermal management systems.
Purpose of the Study:
- To demonstrate a high-contrast, reversible polymer thermal regulator.
- To investigate the potential of crystalline polyethylene nanofibers for active thermal control.
Main Methods:
- Utilized crystalline polyethylene nanofibers exhibiting a structural phase transition.
- Characterized the thermal transport properties across the phase transition temperature.
Main Results:
- Observed a significant, reversible thermal switching ratio averaging ~8x, with a maximum of ~10x.
- The thermal switching occurred within a narrow 10 K temperature range.
- Achieved a switching ratio exceeding previously reported values for solid-state phase transitions.
Conclusions:
- Polyethylene nanofibers offer a promising platform for solid-state thermal regulation.
- The observed high-contrast thermal switching is attributed to a morphology change impacting phonon transport.
- The absence of thermal hysteresis indicates reliable performance over heating/cooling cycles.
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