Self-Assembled Monolayers as Inhibitors for the Atmospheric Corrosion of Copper Induced by Formic Acid: A Comparison between Hexanethiol and Hexaneselenol
2014 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 161, no 1, C50-C56 p.Article in journal (Refereed) Published
The corrosion protection by self-assembled monolayers (SAMs) of hexanethiol and hexaneselenol has been explored on copper exposed to humid air containing formic acid, a corrosive environment relevant for indoor atmospheric corrosion. The kinetics of the formation of corrosion products on SAM covered copper was followed using in-situ infrared reflection/absorption spectroscopy (IRAS) and compared with that of bare copper. Both SAMs initially showed a corrosion protection ability. The prolonged exposure of hexanethiol copper resulted in a reduced formation rate of copper formate and copper hydroxide compared to bare copper, while on bare and hexaneselenol covered samples copper (I) oxide, copper formate, and copper hydroxide were observed. To assess the quality of the SAMs during the sample exposure, vibrational sum frequency spectroscopy (VSFS) was used. It was found that hexaneselenol molecules are locally removed from the surface during corrosion in contrast to their thiol counterparts. This created localized galvanic effects which resulted in an accelerated corrosion of selenol covered copper. X-ray photoelectron spectroscopy at elevated pressure demonstrated that the hexanethiol removed thin oxide layers upon adsorption. A contributing parameter to the enhanced corrosion inhibiting ability of hexanethiol could be its greater ability than hexaneselenol to bind to the copper surface during its deposition and sample exposure.
Place, publisher, year, edition, pages
Electrochemical Society, 2014. Vol. 161, no 1, C50-C56 p.
Sum-Frequency Spectroscopy, Generation Vibrational Spectroscopy, N-Dodecaneselenol Monolayers, Quartz-Crystal Microbalance, Alkanethiol-Covered Copper, X-Ray, Initial Oxidation, Organic-Surfaces, Force Microscopy, Chain-Length
IdentifiersURN: urn:nbn:se:kth:diva-136323DOI: 10.1149/2.056401jesISI: 000330680900041OAI: oai:DiVA.org:kth-136323DiVA: diva2:675787
FunderSwedish Research Council
QC 201312062013-12-042013-12-042014-03-07Bibliographically approved