One-Component Stereoscopic Oligosiloxane-Based Polyurea Radiative Cooling Coatings

Area of Science:

• Materials Science
• Nanotechnology
• Sustainable Energy

Background:

• Passive daytime radiative cooling (PDRC) is a promising zero-carbon cooling technology.
• Existing PDRC materials often suffer from poor mechanical properties and lack self-cleaning capabilities, limiting their practical application and lifespan.
• Developing robust and functional PDRC materials is crucial for widespread adoption.

Purpose of the Study:

• To develop a novel one-component stereoscopic oligosiloxane-based polyurea radiative cooling coating.
• To enhance the mechanical properties, self-cleaning ability, and cooling performance of PDRC materials.
• To provide a sustainable and durable solution for building cooling applications.

Main Methods:

• Fabrication of the coating by integrating blocked amine-oligosiloxane nanoclusters, isocyanate-terminated curing agents, and aluminum oxide (Al2O3) particles.
• Characterization of the stereoscopic oligosiloxane structure and its resulting organic-inorganic hybrid network.
• Evaluation of the coating's mechanical properties (hardness, modulus), infrared emissivity, reflectivity, and cooling performance.

Main Results:

• The developed coating exhibits exceptional hardness (≈227 MPa) and modulus (≈9.7 GPa) due to its highly cross-linked structure.
• The coating achieves a significant cooling effect of ≈9°C below ambient temperature during daytime, attributed to high infrared emissivity and Al2O3 reflectivity.
• Incorporation of polydimethylsiloxane (PDMS) provides excellent self-cleaning and antifouling properties, while fluorinated nanosilica (F-SiO2) imparts superhydrophobicity and water droplet power generation capabilities.

Conclusions:

• The novel stereoscopic oligosiloxane-based polyurea coating offers a durable, self-cleaning, and highly effective passive daytime radiative cooling solution.
• The material's enhanced mechanical and functional properties address key limitations of existing PDRC technologies.
• This PDRC coating presents a sustainable approach for reducing energy consumption in building cooling systems.