Modification of surface-oxidized copper alloy by coupling of viologens for inhibiting microbiologically influenced corrosion

Abstract

Microbiologically influenced corrosion (MIC) is extremely harmful to maritime industries and to the environment. A surface modification technique was developed in this work to impart antibacterial and corrosion-inhibition properties onto the surface-oxidized Cu-Ni alloy to inhibit MIC. Thus, 4-(chloromethyl)phenyl tricholorosilane was first immobilized on the oxidized metal surface to allow the coupling of 4, 4′ -bipyridine to the methyl-chloride groups. Subsequently quaternization by benzyl chloride converted the terminal pyridine groups into pyridinium groups. The success of each functionalization step was ascertained by X-ray photoelectron spectroscopy, atomic force microscopy, and static water contact angle measurement. The quaternized viologen moieties exhibited good bacterial inhibition efficiency at the initial stages of exposure to a seawater-based medium containing aerobic bacteria belonging to the genera Pseudomonas, as revealed by scanning electron microscopy images. The corrosion-inhibition properties of the organic layer were verified by Tafel polarization curves, cyclic polarization curves, and electrochemical impedance spectroscopy. In comparison, the pristine Cu-Ni alloy was readily susceptible to MIC in the same medium and under the same conditions. © 2007 The Electrochemical Society.