Construction\nof Smart Coatings Containing Core–Shell\nNanofibers with Self-Healing and Active Corrosion Protection

Abstract

With\nincreasingly severe metal corrosion, coating preparation with\nhigh-performance corrosion protection has attracted more attention.\nHerein, the encapsulation of the corrosion inhibitor 8-hydroxyquinoline\n(8-HQ) as well as the self-healing agent linseed oil (LO) in polyvinyl\nalcohol (PVA) and chitosan (CS) shells were realized by coaxial electrospinning,\nwhich was recorded as PVA/CS@LO/8-HQ core–shell nanofibers.\nPVA/CS@LO/8-HQ nanofibers were employed to promote the high-performance\ncorrosion protection of the epoxy coating. The anticorrosion mechanism\nwas that the change of the local pH on the metal surface stimulated\nthe release of 8-HQ from the nanofibers, which were then chelated\nwith iron ions to form a complex. When cracks occurred and caused\nrupture of the nanofibers, LO was released and reacted with oxygen\nto cure them so that the cracks could be healed autonomously. The\ndynamic potential polarization curves showed that the corrosion inhibition\nefficiency of the compound inhibitor LO + 8-HQ reached 87.54%, 90.31%,\nand 85.57% at pH = 3, 7, and 11, respectively, higher than that of\nthe single corrosion inhibitor. Density functional theory calculations\nrevealed that the LO and 8-HQ combination, forming a hydrogen bond\ninteraction, promoted the adsorption of inhibitors on the steel surface.\nScanning Kelvin probe and electrochemical impedance spectroscopy proved\nthe self-healing corrosion protection properties of the epoxy coating.\nThese results demonstrated that embedding PVA/CS@LO/8-HQ nanofibers\nin the coating could obtain self-healing properties, and promote the\nmechanical and corrosion protection of epoxy coating.