Passive daytime radiative cooling (PDRC) is an innovative and energy-free cooling technology that automatically cools the surface of an object by reflecting sunlight and emitting heat into outer space without the need for external energy inputs. However, PDRC materials often face issues such as surface contamination and poor long-term outdoor durability. Herein, a photonic structure coating with high PDRC performance, superhydrophobic property, and high outdoor durability was designed and prepared using a phase separation strategy. The photonic structure coating achieves a solar reflectance ∼97.6 % and an average atmospheric window (AW) emissivity of ∼93 %. Under direct sunlight (800 W/m2), the coating exhibits good PDRC performance, with an average temperature drop of ∼13 °C and a maximum temperature drop of up to ∼20 °C. The rough and porous surface of the coating can adsorb air, reducing the solid-liquid adhesion and endowing the coating with super-hydrophobic properties. The incorporation of a small amount of fluoroalkyl silanes into the coating provides water resistance, resulting in a water contact angle (WCA) of ∼155.1° and sliding angle (SA) of ∼2.3°, meeting the need for self-cleaning. Furthermore, the coating exhibits superior durability, including resistance to acid and alkali, UV aging, abrasion, and scratching. All these merits render this photonic structure coating great potential for real-world applications.

中文翻译：

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高性能、超疏水、耐用的光子结构涂层，可实现高效的被动日间辐射冷却


被动式日间辐射冷却 （PDRC） 是一种创新的无能耗冷却技术，它通过反射阳光并将热量发射到外太空来自动冷却物体表面，而无需外部能源输入。然而，PDRC 材料经常面临表面污染和长期户外耐久性差等问题。在此，采用相分离策略设计并制备了一种具有高 PDRC 性能、超疏水性能和高户外耐久性的光子结构涂层。光子结构涂层实现了 ∼97.6% 的太阳反射率和 ∼93% 的平均大气窗口 （AW） 发射率。在阳光直射 （800 W/m2） 下，该涂料表现出良好的 PDRC 性能，平均温降为 ∼13 °C，最大温降高达 ∼20 °C。 涂层粗糙多孔的表面可以吸附空气，减少固液粘附，并赋予涂层超疏水性能。在涂层中加入少量氟烷基硅烷可提供防水性，从而产生 ∼155.1° 的水接触角 （WCA） 和 ∼2.3° 的滑动角 （SA），满足自清洁需求。此外，该涂层还表现出卓越的耐久性，包括耐酸碱、抗紫外线老化、耐磨和耐刮擦。所有这些优点使这种光子结构涂层在实际应用中具有巨大的潜力。