Superhydrophobic VO₂ Nanoparticle/PDMS Composite Films as Thermochromic, Anti-icing, and Self-Cleaning Coatings

Windows are considered as one of the least energy-efficient features of the building envelope. Reducing the associated energy consumption while maintaining comfortable conditions and reasonable transparency is still a serious challenge, which requires intelligent system design. Herein, three hierarchical nano/microstructured films based on vanadium dioxide and polydimethylsiloxane (VO2/PDMS) are fabricated. To our surprise, the striped nano/microstructures give rise to superhydrophobic and oleophobic properties, the contact angles for both water and several organic liquids (e.g., benzyl alcohol, formamide, and ethanolamine) are larger than 150 degrees. A number of desired properties for smart windows are simultaneously endowed for the film, including thermochromic, anti-icing, self-cleaning, and anti-corrosion. Compared with the ordinary glass, the icing delay time of the superhydrophobic surface increases almost eight times at -15 degrees C, and the ice adhesion force reduces to 24.7 kPa. Moreover, the VO2 nanoparticle/PDMS composite film displays remarkable durability against various mechanical and chemical attacks. The unique features render the stripe VO2/PDMS film with great potential to be developed as a generation energy-efficient material and to promote further research of nanomaterials for smart thermal control applications.