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Bioinspired hair-like coating achieves 9 °C radiative cooling
A bilayer surface inspired by insect hair structures combines high solar reflectance with strong mid-infrared emissivity, delivering a temperature reduction of approximately 9 °C through passive daytime radiative cooling – produced via simple, low-cost flocking and scrape coating processes.
Passive daytime radiative cooling (PDRC) materials are attracting considerable attention for applications in power generation and thermal management, as they can reduce surface temperatures without energy input. However, processing complexity, limited substrate compatibility and poor mechanical robustness have hindered their practical deployment. A research team has now developed a bioinspired approach that addresses these limitations.
Drawing inspiration from the hair-like structures found on insects, the researchers designed and fabricated a bioinspired hair-like bilayer surface (BHBS) using two straightforward techniques: scrape coating and electric flocking. This combination offers a simple, low-cost production route that avoids the complex processing typically associated with PDRC materials.
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Outstanding optical and thermal performance
The optimised BHBS sample demonstrated exceptional optical properties, achieving an average solar reflectance of 91.7 % across the 0.3–2.5 µm wavelength range and an average visible reflectance of 97 %. In the critical atmospheric transparency window (8–13 µm), the surface reached an average mid-infrared emissivity of 97.5 %, enabling efficient thermal radiation into outer space.
Under real-world conditions, the bilayer surface delivered a cooling power of 84 W/m² and a temperature drop of approximately 9 °C below ambient – performance figures that confirm its strong potential for PDRC applications on buildings and infrastructure.
Mechanical durability supports practical application
Beyond its optical and thermal performance, the BHBS sample exhibited superior abrasion resistance and good flexibility, addressing two of the key weaknesses that have limited the practical adoption of previous PDRC solutions. The combination of high performance, mechanical robustness and simple fabrication makes this bioinspired surface a promising candidate for scalable passive cooling coatings in energy-saving building and industrial applications.
Source: Shen, C. et al., Bioinspired hair-like bilayer surface for efficient passive daytime radiative cooling. Progress in Organic Coatings 110046 (2026).
