Hydrophobic Radiative Cooling using Zein-Functionalized Polyvinyl Alcohol Nanofibers with Dielectric Nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Textile Engineering

Background:

• Polyvinyl alcohol (PVA) shows potential for radiative cooling due to high infrared emissivity and flexibility.
• PVA's hydrophilicity limits its use in humid conditions, hindering practical applications.
• Developing hydrophobic materials is crucial for advanced cooling technologies.

Purpose of the Study:

• To develop a scalable and eco-friendly hydrophobic material for radiative cooling.
• To enhance the performance of polyvinyl alcohol (PVA) for thermal regulation applications.
• To explore the potential of Zein protein and nanoparticles in composite materials.

Main Methods:

• Incorporation of Zein (a hydrophobic corn protein) into a PVA matrix.
• Addition of aluminum oxide and silicon dioxide nanoparticles to the PVA-Zein composite.
• Fabrication of a composite nanofiber membrane (PZAS) for performance evaluation.

Main Results:

• The PZAS membrane demonstrated significantly enhanced hydrophobicity (water contact angle of 118.5°) compared to pure PVA (≈40°).
• Achieved high solar reflectance (91.7%) and infrared emissivity (96.9%) within the atmospheric transparency window.
• Outdoor tests showed a temperature reduction of up to 6.9°C below ambient temperature.

Conclusions:

• The PZAS composite nanofiber membrane is a viable and sustainable material for radiative cooling.
• Its properties make it suitable for thermal regulation in textiles and wearable cooling devices.
• The material's tunable hydrophobicity and water absorption characteristics suggest potential in biomedical applications.