Cellulose-Based Hierarchical Porous Membranes Integrating Temperature-Adaptability and Superhydrophobic Self-Cleaning...

Area of Science:

• Materials Science
• Sustainable Energy
• Nanotechnology

Background:

• Passive radiative cooling is a promising sustainable technology for building thermal management.
• Current materials face challenges with overcooling in cold climates and performance degradation from outdoor fouling.
• Advanced materials are needed to address these limitations for practical deployment.

Purpose of the Study:

• To develop a cellulose-based material integrating thermochromic switching and superhydrophobic self-cleaning for adaptive radiative cooling.
• To enhance solar reflectance and infrared emissivity for efficient cooling.
• To ensure mechanical robustness and long-term optical stability in outdoor conditions.

Main Methods:

• A cellulose acetate porous network was fabricated using a solvent-template-assisted evaporation-induced phase separation strategy.
• Thermochromic microcapsules (TMCs) were integrated into the porous structure, maximizing Mie scattering and mechanical anchoring.
• Superhydrophobic properties were introduced to achieve self-cleaning capabilities.

Main Results:

• The material demonstrated excellent mechanical properties (21.9 MPa tensile strength, 34.3% elongation at break) even with 30 wt% TMC loading.
• Autonomous optical switching modulated solar reflectance from 96.2% (hot) to 80.8% (cold), with high infrared emissivity (95.0%).
• Field tests showed significant cooling (12.3 °C) and effective suppression of overcooling (6.6 °C advantage), alongside robust self-cleaning (contact angle ~152°).

Conclusions:

• The developed material offers a scalable, eco-friendly solution for next-generation smart building envelopes.
• The integration of thermochromic switching and superhydrophobic self-cleaning provides adaptive thermoregulation and environmental durability.
• This work presents a significant advancement in passive radiative cooling technology for practical building applications.