Fabrication of superhydrophobic films with robust adhesion and dual pinning state via in situ polymerization

Superhydrophobic films on glass substrate with robust adhesion and dual pinning to the water droplets were fabricated utilizing a novel in situ polymerized fluorinated polybenzoxazine (F-PBZ) having drooping aliphatic chains and incorporated SiO2 nanoparticles (SiO2 NPs). By employing the F-PBZ/SiO2 NPs modification, the as-prepared composite films possess the robust adhesion to the glass substrate and superhydrophobic pinned state with water contact angle (WCA) of 150° and the non-pinned state with WCA approaching to 165°. Surface morphological studies have indicated that the wettability of the resultant films could be controlled by tuning the surface composition as well as the hierarchical structures. The key role of micro and sub-micro-sized structures and the nanometer sized voids is discussed by the investigation into static contact angle, contact angle hysteresis, droplet evaporation, and propensity for air pocket formation. The as-prepared films exhibited high adhesion toward the glass substrate with considerable durability in corrosive water and proved their simultaneous use in the transportation of micro-droplets, which could be helpful to design large-area and highly scalable superhydrophobic films.