Application of double click to prepare near-infrared absorbing dye for photo-thermal tuning of cholesteric liquid crystal

Cholesteric liquid crystal (CLC) exhibits selective reflection, making it a great application in the field of light control. Here, a near-infrared light (NIR) was used to drive the self-organizing spiral superstructure of the cholesteric liquid crystal to adjust the reflection notch. The polymer dye M2 with near-infrared absorption properties was synthesized by thiol-ene click polymerization and [2 + 2] click reaction; and has good solubility in the CLC system. M2 absorbs near-infrared light to increase the temperature of the system and the temperature-sensitive chiral dopant CD can realize the photothermal tuning of CLC system by the spiral twisting force of CLC with the change of temperature. The use of near-infrared light is beneficial compared to ultraviolet (UV) and visible light because of its invisibility, high penetration and ease of remote control. The entire CLC system has good near-infrared absorption, fast light response and a wide adjustable range.