Enhancement of structural and charge-transfer barrier properties of n-alkanethiol layers on a polycrystalline copper surface by electrochemical potentiodynamic polarization

Abstract

A method that significantly improves the charge-transfer barrier properties of self-assembled n-alkanethiol films on polycrystalline copper is presented in this paper. Chemically-formed films were further modified electrochemically by repetitive potentiodynamic cycling in ethanolic solutions containing small quantities of n-alkanethiols. The polarization modulation infrared reflection absorption spectra (PM-IRRAS) of the electrochemically-modified thiol films showed an increase in their surface packing density and structure order in comparison to those which were chemically formed. The electrochemical impedance spectra (EIS) revealed that the ability of these films to maintain barrier properties upon exposure to corrosive environments depends directly on their chemical and structural properties, which also influenced the wettability of the surface. Electrochemically-modified thiol films offer superior charge-transfer barrier properties over chemically-formed films.

Hybrid sol-gel/thiourea binary coating for the mitigation of copper corrosion in neutral medium

“…The dynamic parameters associated with polarization curves, such as the corrosion potential (E corr ) and corrosion current (i corr ), were obtained by extrapolating the linear portions of the anodic and cathodic branches to their intersection [24]; the data are summarized in Table 1. The inhibition efficiency () was calculated using the following equation [25]: where i corr • and i corrí represent the current densities of the bare copper and tailored electrodes, respectively. As evidenced from Fig.…”

Assessment of the corrosion protection ability of cysteamine and hybrid sol–gel twin layers on copper in 1% NaCl

“…Fourier transform infrared (FT-IR) spectra of pure CA as well as those of modified electrodes such as Hy/Cu, CA/Cu, Hy/CA/Cu 35 were recorded using JASCO 460 plus model spectrometer in the absorption mode with a frequency range between 4000-400 cm -1 . The IR spectra of the coated substrates were recorded after scratching the respective films formed over copper surface.…”

“…Above this region, a new mixed-kinetics region appeared due to the formation of divalent copper species as a result the current increases steeply was considered as limiting region. [33][34][35] showed that the Hy/CA/Cu electrode not only inhibited the anodic metal dissolution but also suppressed the cathodic oxygen reduction reaction effectively. The dynamic parameters such as corrosion current (i corr ) and corrosion potential (E corr ) were determined by extrapolating the polarization curves and 25 they are summarized in Table 3.…”

“…8,9 SAMs of silica sol-gel have been formed spontaneously by chemisorption which subsequently undergo self-organization process, resulting in the enhanced protection of metals from 30 corrosion. 10 Silane coupling agents have three main advantages: (i) they are commercially available in a large scale, (ii) at one end, they have hydrolysable alkoxy groups capable of reacting with OHrich surface and (iii) at the other end they have a large number of non-hydrolysable organic moieties, which are 35 reactive towards another functional groups and metallic substrates. 11 Among the hybrid silica sol-gel coating materials, epoxy functionalized sol-gel coatings have drawn greater attention not only due to presence of reactive epoxy group but also due to their mild preparation conditions.…”

Structural and Protecting Properties of Functional Organic Coatings on Copper

“…Results evidence that the potential cycling increases the rate of the SAM formation and induces a significant structural changes in the monolayer (7,19). Thioaromatic SAMs on copper were modified by potential cycling in ethanol containing milimolar concentration of 1-dodecanthiol (DT).…”