Chameleon-Inspired Energy-Saving Smart Window Responding to Natural Weather

Energy issues are getting more and more attention, and how to reduce indoor energy consumption while meeting people's daily needs is an important topic. Inspired by the chameleon's discoloration, we fabricated a temperature-responsive energy-saving smart window, which was responsive to natural weather. Temperature was used as a "signal source" to stimulate the gel response, and the gel acts as the "chameleon pigment cell" to control the release of nonionic surfactants acting as the "pigment". A controllable initial lower critical solution temperature of the smart window was achieved with an adjustable range of 24–37 °C. In addition, the introduction of ethylene glycol and an ultraviolet absorber (2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) endowed the gel with the properties of antifreezing and screening ultraviolet rays. The smart windows also exhibited excellent reversibility and sensitivity to temperature and can achieve the effect of controlling indoor temperature and reducing indoor cooling energy. This work may provide a new strategy for solving problems in the field of gel smart windows.