Durable VO₂-Based Thermochromic Paint for Energy-Efficient Opaque Building Facades

Area of Science:

• Materials Science
• Building Science
• Nanotechnology

Background:

• Rising building energy consumption necessitates advanced passive and adaptive envelope technologies.
• Thermochromic materials, particularly Vanadium Dioxide (VO2), show promise for temperature-responsive building thermal management.
• Existing VO2 applications face challenges in durability and implementation on opaque surfaces, lacking design guidelines.

Purpose of the Study:

• To develop a durable, multifunctional thermochromic paint for opaque building envelopes.
• To address limitations of VO2 application, including poor durability and underexplored opaque surface implementation.
• To provide systematic design insights for thermochromic coatings in buildings.

Main Methods:

• Synthesized tungsten (W)-doped VO2@SiO2 core-shell particles for tunable phase transition temperatures.
• Developed a PDMS/epoxy matrix with SiO2 fillers to encapsulate the core-shell particles.
• Evaluated coating properties including superhydrophobicity, adhesion to concrete, vapor permeability, and near-infrared reflectance modulation.

Main Results:

• The W-doped VO2@SiO2 particles exhibited improved oxidation resistance and tunable phase transition temperatures.
• The resulting paint demonstrated superhydrophobicity (contact angle 151°), strong adhesion to concrete (4.85 MPa), and high vapor permeability.
• Near-infrared reflectance increased significantly with VO2 loading, and color-tunable paints were achieved.
• Building model validation showed reduced surface and indoor temperatures, indicating energy-saving potential.

Conclusions:

• The developed thermochromic paint offers enhanced durability, multifunctionality, and improved performance for opaque building envelopes.
• This work demonstrates the feasibility of applying VO2-based coatings to reflection-based opaque surfaces, advancing their practical application.
• Further research is needed to enhance the reflection modulation capabilities of VO2 for greater energy savings in buildings.