Synthesis and characterisation of an iron-ion-responsive coating with core–shell electrospun fibres containing a chelation agent

A self-healing coating containing an electrospun nanofibre encapsulating 3,4,5-trihydroxy benzoic acid cyclohexyl ester (GACE) was prepared. Scanning electron microscopy and transmission electron microscopy demonstrated that the nanofibre had a core–shell structure. The shell thickness of the electrospun fibre was approximately 270 nm, while the core thickness was approximately 380 nm. The self-healing process of the coating containing GACE nanofibres over a carbon steel surface was simulated in a 3.5 wt% NaCl solution for 30 days. Fourier-transform infrared spectroscopy analysis revealed that the synthesised GACE reacted with iron ions and formed a stable Fe–O–C compound, which could repair the scratched coating. The self-repair performance was evaluated through electrochemical measurements, and then a healing model was developed.