Cost-Effective Bilayer Radiative Cooling Paint via a Porous P(VDF-HFP) Top Layer

Global warming has led to an increasing demand for cooling solutions, but traditional cooling technologies consume more electricity and increase carbon emissions. Radiative cooling has emerged as a promising alternative, offering sustainable cooling without electricity consumption. Over the past decade, various material designs have demonstrated radiative cooling performance. Particularly, fluoropolymer-based radiative cooling paints stand out as a practical solution, offering ease of application and scalability. However, its cost is ≈5 times of conventional acrylic paints. By understanding the dependence of reflectance on light wavelength, this study proposes a cost-effective bilayer polymer design with attractive cooling performance. The top porous P(VDF-HFP) layer is effective enough to reflect UV and blue light in the solar spectrum and enhance solar stability while reducing the material usage by ≈70%, and the bottom commercial acrylic latex paint reflects the rest of the solar spectrum. This bilayer paint synergistically exhibits relatively high solar reflectance (≈0.9), moderate material cost (≈$1.3 m⁻²), and excellent UV durability (11 years equivalent). This innovative design achieves a balance between optical performance and economic efficiency, making it a viable candidate for real-world massive implementation of radiative cooling solutions across various applications.