Thermochromic Radiative Cooling Coatings with Robust Superhydrophobicity for Energy‐Efficient Buildings

The rising global demand for energy‐efficient cooling highlights radiative cooling materials as a promising alternative to energy‐intensive air conditioning. However, most existing systems suffer from fixed optical properties, limited adaptability, and poor durability. This work presents a multifunctional, color‐adaptive radiative cooling coating that incorporates thermochromic microcapsules, hexagonal boron nitride, and hollow glass microspheres into a polydimethylsiloxane matrix via a scalable blending process. The coating exhibits a reversible thermochromic transition at ~45 °C, enabling dynamic spectral regulation that enhances solar reflection at elevated temperatures while suppressing overcooling at lower ones. Combined with broadband optical performance (solar reflectance of 91.7% and mid‐infrared emissivity of 94.3%), the coating achieves an average sub‐ambient cooling of 4.44 °C under outdoor conditions and a 6.7 °C reduction compared to commercial coatings in indoor simulation experiments. Beyond cooling efficiency, the micro/nano hierarchical surface imparts robust superhydrophobicity (contact angle >150°), self‐cleaning capability, and long‐term stability in corrosive, humid, and UV‐rich environments. By synergistically integrating adaptive optical regulation, high‐radiative cooling power, and durable surface protection, this work establishes a scalable strategy for next‐generation smart coatings, paving practical pathways toward energy‐saving buildings and sustainable thermal management technologies.