Photo-switchable smart superhydrophobic surface with controllable superwettability

Abstract

New-generation smart surfaces responsive to external stimuli with a controllable wettability have garnered increasing attention in recent years. Notably, a smart surface with a switchable wettability that manifests the facile transition between water-adhesive, rolling isotropic, and rolling anisotropic forms has yet to be explored. Herein, we report the crafting of a superhydrophobic surface with both tunable microstructures and wettability by capitalizing on the azobenzene-containing memory polymer as the substrate. Intriguingly, through photo-manipulation, the azo-polymer film is reversibly and reliably transformed among three wetting states, that is, rose-petal-like water-adhesion, lotus-leaf-like rolling isotropy, and rice-leaf-like rolling anisotropy. Furthermore, the smart superhydrophobic surface is employed as a rewritable platform for droplet transportation. As such, our study expands the category of responsive bio-inspired superhydrophobicity and provides a new strategy to design and access superwetting materials.