Biologically Inspired Scalable-Manufactured Dual-layer Coating with a Hierarchical Micropattern for Highly Efficient...

Bioinspired materials for temperature regulation have proven to be promising for passive radiation cooling, and super water repellency is also a main feature of biological evolution. However, the scalable production of artificial passive radiative cooling materials with self-adjusting structures, high-efficiency, strong applicability, and low cost, along with achieving superhydrophobicity simultaneously remains a challenge. Here, a biologically inspired passive radiative cooling dual-layer coating (Bio-PRC) is synthesized by a facile but efficient strategy, after the discovery of long-horned beetles' thermoregulatory behavior with multiscale fluffs, where an adjustable polymer-like layer with a hierarchical micropattern is constructed in various ceramic bottom skeletons, integrating multifunctional components with interlaced "ridge-like" architectures. The Bio-PRC coating reflects above 88% of solar irradiance and demonstrates an infrared emissivity >0.92, which makes the temperature drop by up to 3.6 °C under direct sunlight. Moreover, the hierarchical micro-/nanostructures also endow it with a superhydrophobic surface that has enticing damage resistance, thermal stability, and weatherability. Notably, we demonstrate that the Bio-PRC coatings can be potentially applied in the insulated gate bipolar transistor radiator, for effective temperature conditioning. Meanwhile, the coverage of the dense, super water-repellent top polymer-like layer can prevent the transport of corrosive liquids, ions, and electron transition, illustrating the excellent interdisciplinary applicability of our coatings. This work paves a new way to design next-generation thermal regulation coatings with great potential for applications.