Self-healing, superhydrophobic coating based on mechanized silica nanoparticles for reliable protection of magnesium alloys

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2016-05, Vol.4 (21), p.841-852
• Main Authors: Ding, ChenDi, Liu, Ying, Wang, MingDong, Wang, Ting, Fu, JiaJun
• Format: Article
• Language: English
• Subjects: Coating; Corrosion prevention; Magnesium base alloys; Nanoparticles; Nanostructure; Self healing materials; Silicon dioxide; Surface chemistry
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c6ta02575g

A new type of host-guest feedback active coating was constructed on a magnesium alloy surface by incorporation of "guest" mechanized silica nanoparticles (MSNPs) as smart nanocontainers into a host self-assembled nanophase particle (SNAP) barrier coating. MSNPs, consisting of mesoporous silica nanoparticles and supramolecular nanovalves in the form of pseudorotaxanes, are capable of blocking entrapped corrosion inhibitor, 2-hydroxy-4-methoxy-acetophenone (HMAP), in mesopores under neutral solution conditions, and only release this chemical upon alkali or Mg 2+ stimuli that corresponds to environmental stimuli occurring on corroding micro-regions of magnesium alloy. The particular alkali/Mg 2+ dual stimuli-responsive release property of the MSNPs endows the physical barrier coating with self-healing potential. Taking advantage of the rough micro/nanostructural surface of the feedback active coating, the superhydrophobic surface was subsequently obtained by modification with 1 H ,1 H ,2 H ,2 H -perfluorodecyltriethoxysilane, and the self-healing superhydrophobic coating was successfully fabricated. The well-designed coating exhibited excellent anticorrosion performance when compared to a reference SNAP coating, and isolated magnesium alloy from aggressive attack in 0.05 M NaCl for 15 days due to the water-repellent surface as well as active protection deriving from the MSNPs. Furthermore, once the surface was mechanically scratched, the alkali/Mg 2+ -triggered release of HMAP from MSNPs formed a compact molecular film on the damaged alloy surface, inhibiting corrosion propagation and executing the self-healing function. Working mechanism of self-healing, superhydrophobic coatings.