Construction of DOPA-SAM multilayers with corrosion resistance via controlled molecular self-assembly

[Display omitted] Although nano “green” coatings with excellent corrosion resistance have attracted great attention, the inhibition efficiency is still limited due to the lack of knowledge about the correlation between molecular structure and anticorrosion performance. Here, we fabricated a series of 3,4-dihydroxy-l-phenylalanine adlayers on self-assembled monolayers (SAMs) with varying end groups. We found that both NH2 and CF3SAMs were more conducive to the adsorption of DOPA and a flat adsorption conformation was preferentially adopted, with the plane of the phenylene ring parallel to the surface via cation-π interactions or hydrophobic interactions, leading to a compact and dense adlayer. Such DOPA-SAM multilayers can effectively protect the substrate from corrosion by suppressing the diffusion of aggressive water and acid molecules as well as the electrodissolution of metals. The lowest corrosion current of adlayers reaches 6.96μAcm−2 which is much lower than that of bare substrate and other anticorrosion surfaces reported previously. The results provide guidance on the design of green anticorrosion materials via selecting SAMs that bridge organic and metal interface.