A novel soft matter composite material for energy-saving smart windows: from preparation to device application

Nowadays, with the increasing energy consumption of buildings and the continuous improvement of human living standards, use of architectural glass with multi-functional features of large-scale manufacturing, safety and energy saving has become the mainstream trend. In this paper, a series of cholesteric side-chain liquid crystal polymers (ChSCLCPs) are designed and synthesized to composite with a widely used laminating material for safety glasses, ethylene-vinyl acetate (EVA), to endow the windows with IR light shielding property. The synthesized ChSCLCPs have the desired reflection wavelengths and thermal stability. Preparation methods of EVA/ChSCLCP composite materials are investigated and different ratios of the contents and various film treatment conditions are attempted. Interestingly, when the contents of EVA and ChSCLCP are equal, sky-blue areas are found under polarized optical microscopy (POM) and the film exhibits stronger light scattering and selective reflection properties. Taking advantages of this phenomenon, a new type of IR shielding film is manufactured by the powder blending method and it not only performs broadband reflection, but also exhibits a strong light scattering. Then, model buildings equipped with and without the film are set up and an energy conservation efficiency of up to 40.4% is obtained, which proves the film's practical applications in energy-saving smart windows.