A Surface-Micellar-Assembled Aerogel for Efficient Building Cooling

Area of Science:

• Materials Science
• Sustainable Energy
• Nanotechnology

Background:

• Passive daytime radiative cooling (PDRC) offers a sustainable solution for building temperature regulation and global carbon neutrality.
• Current PDRC materials often face challenges with particle dispersion stability in polymer matrices, hindering practical use.

Purpose of the Study:

• To develop a novel composite material with enhanced passive daytime radiative cooling performance.
• To address the limitations of poor dispersion stability in existing PDRC materials.

Main Methods:

• Synthesized a composite material using thermally initiated polymerization of acrylamide and calcium ion cross-linking of sodium alginate.
• Incorporated sodium dodecyl sulfate to induce self-assembly and phase separation for improved dispersion and reflectance.
• Utilized freeze-drying to create a 3D skeletal semi-interpenetrating aerogel structure (SAM/SDS-M).

Main Results:

• The resulting SAM aerogel achieved high solar reflectance (0.8934) and infrared emissivity (0.9822) within the atmospheric window.
• Outdoor experiments showed an average indoor temperature difference of 4.04 °C compared to uncovered samples.
• Demonstrated a daytime cooling temperature drop of 8.54 °C under 1040 W/m² solar irradiance, alongside good mechanical strength and thermal insulation.

Conclusions:

• The developed SAM/SDS-M aerogel exhibits excellent PDRC performance, offering a promising solution for sustainable building cooling.
• The strategy of using self-assembly and phase separation provides a pathway for designing stable and high-performance PDRC materials.
• This work contributes to the advancement of practical and efficient PDRC technologies for energy savings and environmental benefits.