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Optically binary liquid crystalline blue phases induced by one-armed cholesterol-linked azobenzene molecules
Leicheng Yin1, Yeping Wu, Jiangang Gao
1Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Centre of Chemistry for Energy Materials, Department of Polymer Science and Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China. zqjm@ustc.edu.cn.
Soft Matter
|July 7, 2015
Summary
Cholesterol-linked azobenzene molecules induce blue phases (BPs) in liquid crystals. UV light triggers photo-responsive phase transitions sensitive to temperature and isomerization degree, enabling patterned optical displays.
Area of Science:
- Materials Science
- Liquid Crystals
- Photochemistry
Background:
- Blue phases (BPs) are temperature-sensitive liquid crystal phases.
- Azobenzene derivatives offer photo-responsive properties.
- Cholesterol-based molecules can induce unique liquid crystal phases.
Purpose of the Study:
- Synthesize and characterize cholesterol-linked azobenzene molecules (CholXAzo).
- Investigate the photo-responsive behavior of CholXAzo in blue phases.
- Explore the relationship between molecular structure, UV irradiation, and phase transitions.
Main Methods:
- Synthesis of CholXAzo molecules with varying spacers.
- UV light irradiation (385 nm) of Chol6Azo doped liquid crystals.
- Polarized optical microscopy (POM) for phase observation.
- Temperature-dependent phase transition analysis.
Main Results:
- Chol6Azo induced blue phases at 4.0 wt%.
- Photo-responsive phase transitions from BP to isotropic phase observed with UV light.
- Phase transition temperature showed sensitivity to isomerization degree (critical 13.7%) and Chol6Azo concentration.
- A phase diagram mapping the optically binary behavior was constructed.
Conclusions:
- CholXAzo molecules enable tunable photo-responsive blue phase liquid crystals.
- The isomerization degree of CholXAzo is critical for controlling phase transitions.
- Demonstrated potential for creating patterned optical displays using these materials.
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