Passive-Cooling Building Coating with Efficient Cooling Performance and Excellent Superhydrophobicity.

Area of Science:

• Materials Science
• Building Science
• Sustainable Energy

Background:

• Passive-cooling building materials offer energy-efficient cooling without external power.
• Existing materials face challenges like high cost, complex fabrication, and toxic solvents.
• These limitations hinder widespread adoption in practical building applications.

Purpose of the Study:

• To develop a facile, high-efficiency, non-toxic, and superhydrophobic passive-cooling building coating (SPCBC).
• To address the limitations of current passive-cooling technologies.
• To facilitate the application of passive-cooling in buildings, especially in hot weather regions.

Main Methods:

• Fabrication of a novel passive-cooling building coating using polydimethylsiloxane and SiO2.
• Characterization of the coating's thermal properties, including reflectance and emittance.
• Evaluation of the coating's cooling performance, durability, and anti-fouling capabilities.

Main Results:

• The fabricated SPCBC exhibited high reflectance and emittance, achieving a 14 °C temperature drop compared to a bare cement surface.
• The coating demonstrated excellent anti-fouling and self-cleaning properties, resisting contamination from various liquids and dust.
• The SPCBC showed outstanding durability, maintaining its superhydrophobicity and cooling performance after 30 days outdoors, 30 days of UV irradiation, and 100 hours of accelerated aging.

Conclusions:

• The developed SPCBC is a cost-effective, non-toxic, and highly effective passive-cooling material.
• Its superior cooling, anti-fouling, and durability characteristics make it suitable for practical building applications.
• This innovation provides a viable solution for energy-saving cooling in buildings globally.