Responsive Photonic Liquid Crystalline Flakes Produced by Ultrasonication

Abstract

Responsive materials that alter their color in response to environmental changes can be used as optical sensors. Chiral nematic liquid crystals are photonic materials that selectively reflect specific wavelengths of light and have been made environmentally responsive. Herein, the use of ultrasonication of responsive cholesteric liquid‐crystal network films to form structurally colored flakes that demonstrate color changes when moved from an aqueous to dry environment and back again is demonstrated, which suggests a scalable technique to form quantities of responsive particles that could conceivably be embedded in permeable hosts to allow the optical detection of humidity or certain chemical species.

Keywords

• additive manufacturing
• cholesteric flakes
• dopants
• effect pigments
• liquid crystals
• polymer photonics