Smart window based on surface-active thermally responsive hydrogel

In the context of the ever-increasing need for energy efficiency, smart windows can significantly contribute to reducing the energy consumption of buildings. Depending on the time of year, however, changing the flow of solar radiation entering through the window allows to reduce the amount of energy spent on either heating or cooling. It is desirable that a smart window reacts passively to changing external temperature or light intensity, changing the influx of solar radiation entering through the window, while not using electrical energy input, complex control circuits and expensive components. Hydrogels made from thermally responsive polymers offer a potential solution for creating simple smart windows that react to external temperature changes. However, existing material technology based on these hydrogels lacks sufficient stability, has a limited number of switching cycles, insufficient light modulation capability, and slow switching speeds between two states. The aim of this project is to develop a practically usable smart window based on thermally responsive hydrogels with novel morphology and chemical composition. The concept involves a thin active surface layer that enables unprecedented operating parameters. The project's goals include achieving 95% light transmission in the transparent state, solar radiation modulation of over 70%, switching speeds between states of approximately one second, and UV and switching stability for at least a five-year device lifetime. As a significant scientific innovation, the project is exploring the addition of novel functionalities to the material. These include switchable color change using plasmon resonance effects and enhanced UV stability and solar radiation modulation through the incorporation of novel photochromic nanoparticles in different hydrogel layers. This approach uniquely combines thermochromic and photochromic properties.