Versatile anti-fouling surface design through nature-inspired approaches

Abstract

Nature-inspired artificial anti-fouling systems, including a superhydrophobic surface, a liquid-infused omniphobic slippery surface and an underwater oleophobic surface, have been proposed and are reviewed herein. An alumina gel film was applied as a platform for a superhydrophobic and an omniphobic slippery surface to ensure mechanical durability of the surface geometry and easy processing. The alumina gel film with hierarchical micro-/nanostructure composed of flower-like texture with 20–50 nm petals over the papilla geometry with a size scale of around 1 mm was prepared using the sol–gel process. The alumina gel film was successfully modified with perfluorodecyl phosphonic acid to introduce superhydrophobicity. Infusion of fluorinated non-volatile fluid into the nanostructured alumina gel film gave omniphobic slippery surfaces for both polar and non-polar liquids. Inspired by the wetting of fish skin and the strong adhesion of mussel adhesive protein, a novel substrate-independent underwater superoleophobic surface was developed. A catechol-bearing polymer was synthesized, which showed strong underwater adhesion with various substrates. Fish skin-inspired nanostructure was then created on this polymer-coated substrate through layer-by-layer assembly of poly(ethylenimine) and a high-molecular weight poly(acrylic acid), resulting in an underwater superoleophobic surface. Upon cross-linking, the obtained oleophobic surface became quite stable in water.