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Alcohol Selective Optical Sensor Based on Porous Cholesteric Liquid Crystal Polymer Networks
Tai-Yuan Yeh1, Ming-Fu Liu1, Ru-De Lin1
1Department of Electro-Optical Engineering, National United University, Miao-Li 360, Taiwan.
Molecules (Basel, Switzerland)
|February 15, 2022
Summary
This study developed a responsive cholesteric liquid crystal polymer (CLCP) film as an optical sensor. The CLCP film can effectively distinguish and quantify methanol and ethanol in mixed solutions based on wavelength shifts.
Area of Science:
- Materials Science
- Polymer Chemistry
- Chemical Sensing
Background:
- Cholesteric liquid crystal polymers (CLCPs) exhibit unique optical properties.
- Developing selective optical sensors for alcohol mixtures remains a challenge.
Purpose of the Study:
- To fabricate a responsive CLCP film for distinguishing methanol and ethanol.
- To investigate the sensor's performance based on porosity and hydrogen bonding.
Main Methods:
- Fabrication of porous CLCP films by removing nonreactive liquid crystal agents.
- Utilizing hydrogen-bonded CLCPs responsive to alcohols.
- Monitoring transmission spectrum wavelength shifts at varying alcohol concentrations and ratios.
- Investigating the effect of UV curing intensity on sensor sensitivity.
Main Results:
- The CLCP sensor demonstrated distinct sensitivities to methanol (0.18 nm/%) and ethanol (1.35 nm/%).
- A linear relationship was observed between wavelength shift and alcohol concentration.
- Sensing sensitivity increased with decreasing methanol-ethanol ratio.
- Higher UV curing intensity enhanced sensitivity and distinguishing ability.
Conclusions:
- Porous CLCP films serve as effective optical sensors for differentiating methanol and ethanol.
- The sensor's response is tunable via porosity and hydrogen bonding.
- CLCPs are promising stimuli-responsive materials for analyzing alcohol mixtures.
