Related Experiment Video
Updated: Jan 6, 2026
06:24
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
6.8K
Rapid and Reversible Visible-Light-Induced Helix Inversion in Chiral Liquid Crystals Doped with a Negative
Hayato Sato1, Takumi Aizawa1, Jiro Abe1
1Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5258, Japan.
Angewandte Chemie (International Ed. in English)
|October 30, 2025
Summary
Researchers developed a new chiral dopant for liquid crystals that rapidly reverses helix structure using visible light. This breakthrough offers faster, reversible light-induced chirality control in advanced materials.
Area of Science:
- Materials Science
- Organic Chemistry
- Photonics
Background:
- Light-induced helix inversion in chiral nematic liquid crystals (N*LCs) is a promising strategy for photoresponsive materials.
- Current N*LC systems face limitations in response speed and reversibility due to inefficient photoisomerization.
Purpose of the Study:
- To develop a novel chiral dopant for rapid and reversible light-induced helix inversion in N*LCs.
- To investigate a new molecular design for efficient photochromic switching and multistage chirality control.
Main Methods:
- Synthesis and characterization of a binaphthyl-bridged imidazole dimer (BN-ImD) as a negative photochromic chiral dopant.
- Investigation of BN-ImD's photoisomerization behavior and helix inversion dynamics in N*LCs under visible light.
- Analysis of sequential helix inversion pathways triggered by light intensity and protonation.
Main Results:
- BN-ImD enables rapid (seconds), visible-light-driven, and fully reversible helix inversion in N*LCs.
- The dopant exhibits efficient isomerization with a large dihedral angle change, functioning in solid films and showing fast thermal back reaction.
- A second-stage, irreversible helix inversion was observed under high-intensity irradiation via protonation, demonstrating distinct switching mechanisms.
Conclusions:
- A new molecular design strategy using BN-ImD offers efficient, rapid, and reversible light-controlled chirality in N*LCs.
- The study demonstrates a novel approach for engineering multistage photoresponsive chiral materials with distinct switching pathways.
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