Natural Light-Regulated Switchable Self-Adhesive Supramolecular Films for Smart Windows

Switchable self-adhesive films are promising coating materials for constructing smart windows. Compared to commonly used hydrogels, self-adhesive supramolecular films have a variety of advantages and serve as a universal carrier of stimuli-responsiveness. In this study, supramolecular adhesive material is processed into self-adhesive films, which display tough and long-term stable adhesion to commercially available organic/inorganic glass windows. Spiropyrans are used as the photo-responsive units to endow smart windows with switchable optical behavior. Reverse photochromism is successfully realized by the combination of supramolecular films and spiropyrans. Reversible and rapid transformations in the color and transmittance of smart windows are fully achieved by natural light irradiation in different weather conditions, including sun, rain, and clouds.