Facile one-step spraying preparation of fluorine-free transparent superhydrophobic composite coatings with tunable adhesion for self-cleaning and anti-icing applications

Transparent superhydrophobic coatings are of vital importance for various rising applications, such as photovoltaics, touch panels, smart windows, etc. However, their large-scale practical applications are severely restricted by hazardous fluorinated reagents, multistep preparation procedures, thermal treatment requirements, and poor durability. In this study, a facile one-step spraying method was proposed to fabricate transparent superhydrophobic coatings on various substrates, using an integrated fluorine-free suspension composed of siloxane-containing acrylate copolymers and SiO2 nanoparticles. Thanks to the incorporation of siloxane groups in the copolymers, the prepared coatings can be cured at room temperature without any thermal curing procedure. The resultant coatings exhibit excellent superhydrophobicity and high transparency, with a WCA of 162.2 +/- 1.8 degrees and similar to 90.83 % transmittance at 550 nm, respectively. Besides, superhydrophobic surfaces with tunable water adhesion can be achieved by adjusting spray pressure. After a series of mechanical durability tests and chemical stability tests, the obtained coatings can still maintain their superhydrophobicity and high transparency. Moreover, the water freezing time on the coated glass can be extended and the ice adhesion strength was significantly reduced, exhibiting excellent anti-icing performance. The facile, fluorine-free, and one-step spraying coating method has scalability and universality, demonstrating the promising prospect of large-scale application in industry.