Enhancing efficient passive daytime radiative cooling in buildings using a durable and robust superamphiphobic coating for long-term performance

Abstract

Passive daytime radiative cooling (PDRC) presents a promising approach to addressing the energy and environmental crises exacerbated by global warming, yet practical applications are often limited by poor durability and susceptibility to surface contamination. To address these challenges, this study reports the successful fabrication of a porous superamphiphobic MgO/SiO2 radiative cooling coating with enhanced environmental durability using a facile water-induced phase separation approach. Indoor and outdoor experiments and material characterizations show that this coating has a significant solar reflectance (95.04%) and a high emissivity (96.67%) within the atmospheric transparency window (ATW). Under outdoor conditions with a mean solar irradiance of 745 W/m2 and relative humidity of 70%, the coating attains a peak sub-ambient temperature drop of 7.22 °C. Moreover, the superamphiphobic MgO/SiO2 coating demonstrates excellent self-cleaning capability, effectively repelling common contaminants such as milk and tea. Its environmental durability is rigorously validated through abrasion, water impact, and adhesive tape peeling tests, confirming long-term stability under realistic outdoor conditions. Comparative energy analysis reveals the coating achieves 71.3% higher cooling energy savings compared to commercial white coatings, with significant long-term economic benefits. This work provides a comprehensive solution for developing durable, efficient, and economically viable radiative cooling coatings for sustainable building thermal management.