Facile Synthesis of Smart Nanocontainers as Key Components for Construction of Self-Healing Coating with Superhydrophobic Surfaces

摘要

SiO~(2)-imidazoline nanocomposites (SiO~(2)-IMI) owning high loading capacity of corrosion inhibitor, 1-hexadecyl-3-methylimidazolium bromide (HMID), and a special acid/alkali dual-stimuli-accelerated release property have been synthesized via a one-step modified St?ber method. SiO~(2)-IMI were uniformly distributed into the hydrophobic SiO~(2) sol to construct “host”-“guest” feedback active coating with a superhydrophobic surface (SiO~(2)-IMI@SHSC) on aluminium alloy, AA2024, by dip-coating technique. SiO~(2)-IMI as “guest” components have good compatibility with “host” sol-gel coating, and more importantly, once localized corrosion occurs on the surface of AA2024, SiO~(2)-IMI can simultaneously respond to the increase in environmental pH around corrosive micro-cathodic regions and decrease in pH near micro-anodic regions, promptly releasing HMID to form a compact molecular film on the damaged surface, inhibiting corrosion spread and executing a self-healing function. The scanning vibrating electrode technique (SVET) was applied to illustrate the suppression process of cathodic/anodic corrosion activities. Furthermore, benefiting from the superhydrophobic surface, SiO~(2)-IMI@SHSC remained its protective ability after immersion in 0.5?M NaCl solution for 35?days, which is far superior to the conventional sol-gel coating with the same coating thickness. The facile fabrication method of SiO~(2)-IMI simplifies the construction procedure of SiO~(2)-IMI@SHSC, which have great potential to replace non-environmental chromate conversion coatings for practical use.