Protection of zinc from corrosion by coverage with a hydrated cerium(III) oxide layer and ultrathin polymer films of a carboxylate self-assembled monolayer modified with alkyltriethoxysilanes

Abstract

Ultrathin films of one- and two-dimensional polymers were prepared on a zinc electrode coated with a hydrated cerium(III) oxide Ce 2O 3 layer by modification of a 16-hydroxyhexadecanoate ion HO ( CH 2 ) 15 CO 2 - ( HOC 16 A - ) self-assembled monolayer (SAM) with alkyltriethoxysilanes. The protective efficiency, P of the film was determined by polarization measurements of the electrodes bare and covered with the polymer films in an oxygenated 0.5 M NaCl solution. The respective P values for the one-dimensional polymers of the HOC 16A − SAM modified with octyltriethoxysilane C 8H 17Si(OC 2H 5) 3 (C 8TES) and octadecyltriethoxysilane C 18H 37Si(OC 2H 5) 3 (C 18TES) were 94.4 and 95.1%. The values for the two-dimensional polymers of the HOC 16A − SAM modified with 1,2-bis(triethoxysilyl)ethane (C 2H 5) 3Si(CH 2) 2Si(C 2H 5) 3 plus C 8TES and C 18TES were 95.4 and 96.5%, respectively, indicating higher than those of the one-dimensional polymers. Structures of the polymer films were characterized by contact angle measurement with a drop of water and X-ray photoelectron and FTIR reflection spectroscopies.