Facile spraying fabrication of highly flexible and mechanically robust superhydrophobic F-SiO2@PDMS coatings for self-cleaning and drag-reduction applications

Abstract

Superhydrophobic coatings treated as surface functional materials are endowed with great application potential with respect to self-cleaning, drag-reduction, anti-icing, etc. In this study, we fabricated a highly flexible and mechanically robust superhydrophobic F-SiO₂@PDMS coating through a facile layer-by-layer strategy. It was demonstrated that PDMS played a crucial role of binder for immobilizing the F-SiO₂ nanoparticles and improving their adhesion to substrate materials. Meanwhile, the PDMS layer endowed the superhydrophobic coating with superior mechanical flexibility. Finally, the as-constructed superhydrophobic coating exhibited excellent water-repellency with a high water contact angle of 156.5° and low sliding angle of only 2.0°. Furthermore, the water adhesion strength on the superhydrophobic coating was only 2 μN, indicating its ultralow viscous resistance to dynamic moving water droplets. The superhydrophobic F-SiO₂@PDMS coating was independent of the substrates without any limitations, and they exhibited high flexibility and mechanical robustness with the elongation ratio reaching 83.3% under the conditions of high superhydrophobicity. Also, the superhydrophobic coating exhibited strong durability under the severe environments of corrosion and mechanical abrasion. Thus, the as-fabricated highly flexible and mechanically robust superhydrophobic F-SiO₂@PDMS coating is considered to be an ideal candidate for applications in the fields of self-cleaning and drag-reduction.