Flexible adaptive solar control smart-films comprising thermo-responsive hydrogels with silver naopatterned substrates

Smart windows adaptively screen the sunlight that enters into the room, thereby reducing the cooling cost by restraining the increase of room temperature. Traditional glass-based smart windows have been extensively studied, but it is difficult to manufacture the curved or flexible glazings. In this study, we developed a film-type hybrid smart windows that can show the tansmittance change in response to both external temperature and electric energy, which is achieved by using the thermosensitive hydrogel and transparent silver nanopatterned film. The thermosensitive hydrogel was injected in the space between the films, and the optical transition from transparent to opaque state can be induced by the phase transition of the thermosensitive hydrogel. We found that the silver nanopatterned films effectively generated the heat by the Joule-heating mechasim, leading the phase transition of the hydrogels. Consequently, the aggregated hydrogel chain scattered the light passing through the film, reducing the optical transmittance.