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 degrees and a sliding angle of 4.2 degrees . The air cushions captured by the hierarchical micro/ nano structures reduced the contact area between water droplets and the MN -surface, giving it excellent selfcleaning 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.