Preparation of one-dimensional polymer films by modification of a hydroxymethylbenzene self-assembled monolayer on iron with alkyltriethoxysilanes for preventing iron corrosion

Abstract

A self-assembled monolayer (SAM) of p-hydroxymethylbenzene HOCH 2C 6H 4 – (HOMB) moiety adsorbed on iron by the formation of a covalent bond between carbon and iron atoms was prepared by electrochemical derivatization of an iron electrode with p-hydroxymethylbenzenediazonium tetrafluoroborate HOCH 2C 6H 4N 2BF 4. The electrode covered with the HOMB SAM was modified with alkyltriethoxysilanes C n H 2 n+1 Si(OC 2H 5) 3 (C n TES, n = 8 or 18) to prepare a film of one-dimensional polymer. The protective ability of the polymer film was determined by polarization measurement of the covered electrode in an aerated 0.5 M NaCl solution. The ability was enhanced by modification of the HOMB SAM with C n TES markedly. The iron surface coated with the one-dimensional polymer film of the HOMB SAM modified with C 8TES was characterized by contact angle measurement and FTIR reflection and X-ray photoelectron spectroscopies. The persistence in the protective ability of the polymer film against iron corrosion in 0.5 M NaCl may be associated with the strong adsorption via the covalent bond, revealed by electron-probe microanalysis.