Non-Wetting Superhydrophobic Surface Enabled by One-Step Spray Coating Using Molecular Self-Assembled Nanoparticles

Inspired by nature, creating an artificial superhydrophobic surface would have broad implication in many industries. Although various fabrication approaches have been developed, low-cost pathways for integration into large-area superhydrophobic coating remain a considerable challenge. Herein, we developed a fast, facile, and scalable approach for the fabrication of superhydrophobic surfaces via one-step spray coating process. The nanoparticle solution for the film coating was prepared by functionalizing the hydrophilic surface of Al2O3 nanoparticles by self-assembly of phosphonic acid based hydrocarbon molecule. After well dispersion in solution, the functionalized Al2O3 nanoparticles were simply spray-coated for fabricating the superhydrophobic hierarchical structures without post-hydrophobization. The surface morphologies and wetting properties of the developed coating were characterized to optimize the superhydrophobicity. Consequently, our optimized one-step coating method allows excellent non-wetting superhydrophobic surface with morphology controlled and densely packed hierarchical structures, exhibiting a high water contact angle (>160 degrees) with a low sliding angle (<2 degrees). Furthermore, this method was applied to diverse substrates including silicon, glass, fabric, and even flexible plastic substrates.