A robust and low-adhesion superhydrophobic quaternized chitosan-based film with hierarchical micro/nano structures.

Quaternized chitosan (QCS)-based films are garnering considerable attention owing to their multifunctional properties; however, their inherent hydrophilicity limits their application. In this study, a fluorine-free superhydrophobic surface for QCS-based film was fabricated using an easy and effective method. The film with hierarchical micro/nano structures (MN-surface) was fabricated by combining the template and spray methods. After modification with polydimethylsiloxane, the MN-surface showed excellent superhydrophobicity, with a water contact angle of 165.7° and a sliding angle of 4.2°. The air cushions captured by the hierarchical micro/nano structures reduced the contact area between water droplets and the MN-surface, giving it excellent self-cleaning ability. Additionally, the microstructures acted as a protective layer for the nanostructures, protecting them against damage during mechanical wear. Thus, the MN-surface exhibited remarkable mechanical robustness against sandpaper abrasion, tape peel-off, bending, stretching, and water flow impact. More importantly, it showed an excellent anti-adhesion effect on bacteria, thereby further lowering the risk of bacterial invasion. Consequently, the superhydrophobic QCS-based film opens up new possibilities for its application in diverse fields. [Display omitted] • The robust superhydrophobic quaternized chitosan-based film was prepared. • The surface exhibits outstanding adhesion properties and self-cleaning ability. • The formed hierarchical micro/nano structures can enhance its mechanical stability. • The surface shows good resistance to high-speed jets and continuous water flow. • The surface has significantly reduced bacterial adhesion by 95.2 %. [ABSTRACT FROM AUTHOR]