image: Temperature-responsive optical regulation helps wood surfaces reflect more solar radiation while maintaining thermal emission for passive cooling.
Credit: Yunnan Provincial Key Laboratory of Wood and Bamboo Biomass Materials, Southwest Forestry University, Kunming 650224, China weigao@swfu.edu.cn.
Radiative cooling offers a way to manage heat without continuous electricity input, but many existing materials face challenges related to processing complexity, outdoor durability, contamination, and large-area application. Wood provides an attractive substrate because of its renewability and established use in buildings, yet its natural surface has limited ability to regulate solar absorption and thermal radiation.
In this study, researchers constructed a temperature-responsive cooling surface by combining thermochromic microcapsules with ZnO nanoparticles in a phenolic resin coating. The ZnO nanoparticles were synthesized in situ within the resin and then applied to rubberwood and fir through a multilayer spraying process. The resulting micro/nanostructured surface not only improved water repellency and self-cleaning behavior, but also provided UV protection.
The coating showed a clear thermochromic response around 28 °C. When the temperature exceeded this transition point, solar reflectance in the UV-visible range increased by approximately 44.7%, while thermal absorptance in the 8–13 μm atmospheric window remained high. This combination allowed the surface to reduce solar heat absorption while continuing to release thermal radiation.
Outdoor tests demonstrated a maximum surface temperature reduction of 10.4 °C and a subsurface reduction of 7.2 °C for the optimized modified rubberwood. A model wooden house showed average reductions of 3.3 °C at the surface and 2.5 °C indoors compared with the control. EnergyPlus simulations across 10 representative cities further suggested that annual cooling energy savings could reach 19.5% in hot climates.
The authors note that repeated rainfall and mechanical abrasion remain important issues for future evaluation. Nevertheless, the results demonstrate a practical route for combining temperature-responsive optical regulation with wood-based building materials.
See the article:
DOI
https://doi.org/10.1016/j.jobab.2026.100301
Original Source URL
https://www.sciencedirect.com/science/article/pii/S2369969826000733
Journal
Journal of Bioresources and Bioproducts
Journal
Journal of Bioresources and Bioproducts
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Fabrication of Radiative Cooling Function on Wood Surface via TCMs@ZnO
Article Publication Date
5-Sep-2026