Thermochromic hydrogels for thermal management smart windows

Thermal management smart windows can regulate indoor temperature by adjusting the intensity or spectral distribution of incoming solar radiation. This functionality helps reduce the energy demand of heating, ventilation, and air-conditioning (HVAC) systems, thereby contributing to energy conservation, emission reduction, and the achievement of carbon neutrality. Thermochromic hydrogels, with their intrinsic temperature responsiveness, broadband optical modulation capability, facile tunability, and low cost, have become ideal thermochromic materials for thermal management smart windows. This review focuses on thermochromic hydrogels for thermal management smart windows and introduces the research progress of intrinsic thermochromic hydrogels and their thermal management smart windows from the perspectives of chemical modification strategies and physical modification strategies. Then, the research progress of composite thermochromic hydrogels and their applications in thermal management smart windows is systematically reviewed, with particular emphasis on the incorporation of photothermal conversion fillers and thermochromic components. Moreover, current challenges and potential improvement strategies of thermochromic hydrogels for thermal management smart windows are identified and discussed. The aim of this review is to systematically summarize the optimization strategies for thermochromic hydrogels in thermal management smart windows and to provide guidance for future in-depth research, thereby promoting the advancement and application of thermochromic hydrogels for smart windows.