Polymer Network Film with Double Reflection Bands Prepared Using a Thermochromic Cholesteric Liquid Crystal Mixture

Area of Science:

• Materials Science
• Polymer Chemistry
• Optics

Background:

• Cholesteric liquid crystal polymer network (CLCN) films are utilized for decorative and anticounterfeiting purposes.
• CLCN films with double reflection bands offer enhanced suitability for these applications compared to single reflection band films.

Purpose of the Study:

• To develop a method for preparing CLCN films with double reflection bands.
• To explore the application of these films in decorative patterns and potentially in display technologies.

Main Methods:

• A two-step photopolymerization approach was employed using thermochromic cholesteric liquid crystals (CLCs).
• The first polymerization step occurred near the substrate at a specific temperature, influenced by oxygen inhibition.
• The second polymerization step occurred near the air at a different temperature, controlling the second reflection band.

Main Results:

• The wavelengths of the two reflection bands were successfully controlled by the distinct polymerization temperatures used in each step.
• Composite color patterns were fabricated, demonstrating suitability for decorative applications.
• A double-layered CLCN film exhibiting a broad reflection band was successfully prepared.

Conclusions:

• The two-step photopolymerization method provides effective control over the reflection bands of CLCN films.
• The developed CLCN films are suitable for decorative applications and show potential for use in display technologies.