Thermo-responsive smart window based on laminated glass with aramid-hydrogel hybrid as an interlayer

Colorless aramids were synthesized and used as reinforcing agents. These aramids were dissolved in N,N-diethylacrylamide along with a crosslinking agent, then UV-cured to produce aramid–hydrogel hybrid films. Increasing the aramid content led to lower water content and a higher tensile strength. The hydrated films transmitted visible light at 25 °C; however, transmittance decreased with increasing temperature, exhibiting a lower critical solution temperature near 35 °C. The hydrated films were laminated between two glass sheets, with the edges sealed using a hot-melt film, to fabricate smart window devices based on laminated glass. The smart window exhibited the most effective damping and the highest noise absorption at a given aramid content. No moisture evaporation or leakage occurred, even after repeated use. The laminated film was manufactured in the same manner and did not break even when bent severely. The smart windows demonstrated high switching speed (222.2%/s for response; 37.7%/s for recovery) and whiteness (81.1 at 40 °C), enabling their use as screens or reflectors capable of reversibly displaying images. Smart windows containing fluorescent dyes exhibited high chroma at elevated temperatures, while showing high fluorescence chroma at lower temperatures. Additionally, smart windows incorporating thermochromic pigments exhibited a reversible transition from a specific color (e.g., red, yellow, blue) to white, depending on the temperature.