Mechanically durable and self-healing super-hydrophobic coating with hierarchically structured KH570 modified SiO2-decorated aligned carbon nanotube bundles

We prepared stably and hierarchically structured particles (ACNTB-SiO2-KH570) composed of silane coupling agent 3-methacryloxypropyltrimethoxysilane (KH570) modified nano-SiO2 and aligned carbon nanotube bundles (ACNTB), and developed a mechanically durable super-hydrophobic composite coating from epoxy (EP) adhesive precursor and ACNTB-SiO2-KH570 by dripping method, without using any fluoro-containing compounds. The results show that ACNTB-SiO2-KH570 particle film possesses excellent super-hydrophobicity because of the complicated nanotexture of ACNTB-SiO2-KH570. The composite coating with a very small content (4.3%) of ACNTB-SiO2-KH570 can show excellent super-hydrophobicity owing to the formation of rough surface with micro/nanoscale hierarchical structure. The water contact angle (CA) and sliding angle (SA) of the composite coating can reach 158.8 ± 2.5° and 2.5 ± 0.5°, respectively. Moreover, the composite coating not only displays good antifouling and self-cleaning performance, but also retains super-hydrophobicity after sand falling test, water jet impact and sandpaper abrasion cycles. The excellent mechanical durability of the composite coating is attributed to the synergistic effects of high strength and toughness ACNTB-SiO2-KH570 and the good interface interaction of the different components in coating. The composite coating can show good adhesions to various substrate and exhibit super-hydrophobicity. Furthermore, the damaged composite coating can recover its super-hydrophobicity after being heated to 300 °C, owing to the combination of the decomposition of partial EP polymers and the migration of SiO2 to the coating surface.