Smart coating with dual-pH sensitive, inhibitor-loaded nanofibers for corrosion protection

Smart coatings that provide corrosion protection on demand have received a lot of recent attention. In the present study, nanofibers containing a corrosion inhibitor were prepared by a coaxial electrospinning technique, which addresses the limitations of inhibitor-loaded microcapsules or nanocontainers. The as-prepared nanofibers have a core-shell structure with Ce(NO3)3 and the chitosan/polyacrylic acid polyelectrolyte coacervate as the core and shell materials, respectively. UV-vis spectroscopic analysis confirms that the nanofibers are pH-sensitive and able to release the enclosed Ce(NO3)3 at both low and high pH conditions, which are spontaneously generated during corrosion at local anodes and cathodes, respectively. A coating system consisting of such nanofibers within a polyvinyl butyral coating matrix exhibits improved corrosion protection of an AA2024-T3 substrate. Moreover, the embedded Ce(NO3)3-loaded nanofibers can persistently release Ce(NO3)3 to impede corrosion of AA2024-T3 when the artificially damaged coating sample is exposed to NaCl solution.