Flexible, broadband, super-reflective infrared reflector based on cholesteric liquid crystal polymer

Abstract

Cooling indoor spaces in hot weather conditions requires a significant amount of energy. To reduce energy consumption, light control of windows and facades in buildings is a great way. In this study, we propose a facile method to fabricate a flexible cholesteric liquid crystal (CLC) polymer reflector that can control the reflection of infrared (IR) light selectively without interfering with visible light. To this end, we fabricated a flexible super-wideband IR reflector using right- and left-handed chiral reactive mesogens. The fabricated IR reflector exhibited several desirable properties, including thinness, high mechanical stability and flexibility, strong durability, solvent- and acid resistance, high transparency, and low haze in visible light. The fabricated IR reflector was observed to reduce the indoor temperature by 6 °C compared to the outside temperature. This proves that, by insulating the incident heat, the proposed IR reflector can be utilized to maintain low indoor temperatures in working and living spaces. The flexible and super-reflective CLC film reported in this study is expected to be a promising candidate in several applications, including anti-IR devices, energy-saving windows for cars, and facades of modern buildings.