High Performance Radiative Cooling Coating with Dense Surface Structure via Closed-Cell Microstructures and Uniformly Dispersed Scatterers.

Passive daytime radiative cooling (PDRC) coatings offer a sustainable solution for building thermal management. A key barrier to widespread adoption of PDRC coatings is the simultaneous attainment of high solar reflectance and long-term durability. Here, a novel strategy is employed to pave a potential way to address this challenge. This novel strategy involves reduction of TiO agglomeration in waterborne coatings via a rheology-based method to enhance Mie scattering, and incorporation of closed-cell microstructures to augment light scattering while preserving the surface film integrity. The results exhibit high infrared emissivity (94.9%) and solar reflectance (90.8%), achieving a daytime cooling temperature of 7.63 °C under direct sunlight. Moreover, its durable, dense surface structure ensures exceptional outdoor performance, including robust adhesion, excellent thermal stability, strong resistance to acid/alkali and UV, and high fouling resistance. Coupled with its low cost and scalability, this novel technique can be an excellent candidate for widespread PDRC building applications and contribute to reduced carbon emissions from building cooling.