Innovative Applications Enabled by the Versatile Structural Color of Cholesteric Liquid Crystals

Area of Science:

• Materials Science
• Photonics
• Liquid Crystal Technology

Background:

• Cholesteric liquid crystals (CLCs) are known for Bragg reflection and structural color.
• Traditional applications of CLCs are limited, primarily in thermometry.
• Recent advancements enable new CLC formulations and processing techniques.

Purpose of the Study:

• To review novel applications of CLCs leveraging recent formulation and processing advancements.
• To highlight CLC-based materials for societal and industrial relevance.
• To discuss the transition from proof-of-concept to commercial application.

Main Methods:

• Formulation of CLC mixtures with reactive mesogens for post-polymerization stability.
• Advanced liquid processing techniques: microfluidic emulsions, 3D printing, fiber spinning.
• Development of Cholesteric Spherical Reflectors (CSRs) and CLC elastomer (CLCE) materials.

Main Results:

• CSRs enable Physical Unclonable Functions for secure authentication and machine-readable patterns.
• CSRs offer novel coloring solutions, including nonspectral colors like gray.
• Polymerized CLC films provide visually unobtrusive solar panel camouflage with minimal efficiency loss.
• CLCE films and fibers demonstrate colorimetric strain monitoring for structural health and wearable applications.

Conclusions:

• Recent advances in CLC formulation and processing unlock diverse, high-impact applications.
• CLC-based materials offer unique solutions in security, energy, and structural monitoring.
• Further research is needed to address scale-up challenges for commercial production.