Superamphiphobic and flame-retardant coatings with highly chemical and mechanical robustness

Abstract

• A multifunctional superamphiphobic and flame-retardant coating is prepared. • Overhanging re-entrant structures are constructed by a simple spaying approach. • The surface has high mechanical/chemical resistance. • The coating offers self-extinguishing property to flammable substrates. Developing superamphiphobic coatings/surfaces with integrated flame-retardancy, mechanical robustness and corrosion resistance is significant for applications in ordinary life, chemical engineering, radionuclide separation and sewage treatment but still remains challenging, due to difficulty of simultaneously demonstrating these features. Here, a multi-functional coating, consisting of functionalized silica nanoparticles, micro-sized ammonium polyphosphate particles and fluorinated alkyl silane, is constructed. By virtue of a simple and cost-effective spaying approach, a unique randomly overhanging re-entrant and hierarchical structure can be constructed on a wide range of substrates, showing super-repellency to water and oils with low surface tensions. The created superamphiphobic surface demonstrates extremely high stability under exposure to strong corrosive chemicals (namely aqua regia, concentrated sulfuric acid and sodium hydroxide), cyclic mechanical abrasions, UV irradiation, and heat treatment. More importantly, such coating offers high flame retardancy and self-extinguishing property to flammable substrates, and the superamphiphobicity is retained even after burning. Featuring with easy processability, multi-functions and high endurance, the coating is promising for applications with multi-tasks and fire-safety requirements.