On behalf of the Department of Building Environment and Energy Engineering (BEEE) at The Hong Kong Polytechnic University, we are delighted to share that a research team at the International Centre of Urban Energy Nexus (UEX) has developed an innovative smart window film that can automatically regulate indoor light and humidity in response to environmental changes. This breakthrough offers a promising solution for reducing building energy consumption and supporting the development of low-carbon cities.
As global warming intensifies, window technologies that can adapt to changing environmental conditions are increasingly important. The newly developed smart window film is designed to lower indoor temperatures during the day while absorbing moisture and reducing transparency at night, thereby enhancing energy efficiency, indoor comfort, and privacy. Antibacterial, durable, and cost-effective, the innovation is particularly suitable for humid regions such as Hong Kong and holds strong potential for green building applications.
Known as the “Moisture-responsive and Light-regulating” (MRLR) film, this PolyU innovation was led by Prof. YAN Jinyue Jerry, Chair Professor of Energy and Buildings, and Dr LIU Junwei, Research Assistant Professor of BEEE. The team has transformed traditional window film design by adopting a dual-layer structure composed of a hydrophilic polyacrylonitrile (PAN) nanofiber layer and a transparent polyacrylamide (PAAM) hydrogel with excellent water retention. By leveraging the water absorption and evaporation characteristics of these materials, the film is able to regulate light, heat, and humidity simultaneously.
This innovative development demonstrates the research excellence and commitment of BEEE and PolyU in advancing sustainable building technologies and contributing to a greener, more resilient urban future.
BEEE congratulates Prof. YAN, Dr LIU, and the entire research team on this outstanding achievement.
For details, please refer to https://www.polyu.edu.hk/media/media-releases/2026/0610_polyu-develops-smart-window-film-to-regulate-light-and-humidity/
