Design of VO2-based photoactuators for smart windows

Smart windows can slow down the heating rate in buildings to a certain extent and realize energy savings and emission reduction. Various approaches have attempted to make windows ‘smart’ by tailoring their thermal insulation behavior in response to environmental changes. However, there is still room for further improvement in their efficiency and automation performance. Here, based on photothermal functional fillers and shape memory substrates, a new type of photoactuator for smart windows—passively controlled shuttering—was designed. The photoactuator was composed of VO 2 @SiO 2 and methyl methacrylate butyl acrylate polymer (MBP). These two functional components had similar transition temperature (30 °C), and the photothermal conversion of VO 2 @SiO 2 stimulated the shape memory behavior of the composite. It was demonstrated that the intelligent performance was closely related to the shape memory properties of MBP and the phase transition characteristics of VO 2 NPs, which synergistically modified the solar regulation ability. The results suggest that this new type of optical driving window has potential applications in the field of wearable sensors, energy conservation and medical devices.