Adaptive 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. In this work, we present 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 system achieves sub-ambient cooling of 7.2 °C under outdoor conditions and a 6.7 °C reduction compared to commercial coatings in the indoor simulation experiment. 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.