Self-assembled monolayers of p-toluene and p-hydroxymethylbenzene moieties adsorbed on iron by the formation of covalent bonds between carbon and iron atoms for protection of iron from corrosion

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• 作者：Tadashi Shimura ; Kunitsugu Aramaki
• 关键词：A. Iron ; B. Polarization ; B. Contact angle measurement ; C. Self-assembled monolayer ; C. Covalent adsorption bond
• 刊名：Corrosion Science
• 出版年：2007
• 期刊代码：28_0010938x
• 类别：ch
• 出版时间：March 2007
• 卷：49
• 期：3
• 页码：1378-1393
• 文件大小：517 K

摘要

An iron electrode was modified by electrolytic reduction in deaerated acetonitrile solution of p-toluenediazonium tetrafluoroborate CH₃C₆H₄N₂BF₄ (TDFB) or p-hydroxymethylbenzenediazonium tetrafluoroborate HOCH₂C₆H₄N₂BF₄ (HOTDFB) below 10 °C to form a self-assembled monolayer (SAM) of toluene CH₃C₆H₄– or hydroxymethylbenzene HOCH₂C₆H₄– (HOMB) moiety, probably adsorbed on the electrode by the formation of a covalent bond between carbon and iron atoms, as shown in references. The protective ability of the layer was examined by polarization measurement of the electrode in an aerated 0.5 M NaCl solution. The protective efficiencies of these two SAMs were not high, around 30%, a little higher than that of the toluenethiol CH₃C₆H₄SH SAM which was anchored on iron via a coordinate bond between sulfur and iron atoms. The iron surfaces modified with TDFB and HOTDFB were characterized by contact angle measurement, FTIR reflection spectroscopy and X-ray photoelectron spectroscopy. The persistence in protection of iron against corrosion by coverage with the HOMB SAM was confirmed by polarization measurements after immersion in 0.5 M NaCl for a long period of the time.