Protection of Iron Corrosion by Coverage with an Ultrathin Two-dimensional Polymer Coating Prepared by Chemical Modification of Carboxylate Ion Self-Assembled Monolayer Adsorbed on Passivated Iron

Abstract

An ultrathin （nm order of the thickness）, two-dimensional polymer coating was prepared on the passive film formed in a borate buffer at pH 8.49 by modification of 16-hydroxyhexadecanoate anion HO（CH₂）₁₅CO₂^－ self-assembled monolayer with 1, 2-bis（triethoxysilyl）ethane （C₂H₅O）₃Si（CH₂）₂Si（OC₂H₅）₃ and octadecyltriethoxysilane C₁₈H₃₇Si（OC₂H₅）₃. The electrode covered with the passive film and two-dimensional polymer was treated in 0.1 M NaNO₃ to heal the passive film. The time for passive film breakdown of the complex film, t_bd was markedly long, expecting more than 1000 h and the protection efficiency, P（％） was extremely high, more than 99.9％, unless the passive film breakdown occurred. Complete protection against passive film breakdown and markedly high value of P can be investigation of ultimate protective coatings for SDGs in future.