Superamphiphobic Coatings from Combination of a Biomimetic Catechol-Bearing Fluoropolymer and Halloysite Nanotubes

Superamphiphobic coatings with remarkable water and oil repellency are prepared by the combination of a biomimetic catechol-bearing fluoropolymer, poly{2-(perfluorooctyl)ethyl acrylate-co-N-(3,4-dihydroxyphenethyl) acrylamide} (P(FAC(8)-co-DOPAm)), and naturally available halloysite nanotubes (HNTs). They are based on surface modification of HNTs with P(FAC(8)-co-DOPAm). A procedure to attain stable affinity between silica and the copolymer is established, and used for surface modification of HNTs. Superamphiphobic coatings are obtained by casting the suspension of P(FAC(8)-co-DOPAm)-modified HNTs onto substrates. The superamphiphobic coatings exhibit Cassie-Baxter's wetting to liquids with a wide range of surface tension, because of the extremely low surface free energy and the unique micro-/nanohierarchical surface topography, as well as the re-entrant curvature of HNTs. These superamphiphobic coatings are environmentally and chemically durable, and can resist water scouring. The abundance of HNTs in nature and the easily controlled process of this method ensure an efficient approach for large-scale production of superamphiphobic coatings for various applications.