State of the surface of antibacterial copper in phosphate buffered saline

Toparli C, Hieke SW, Altin A, Kasian O, Scheu C, Erbe A (2017)

Publication Type: Journal article

Publication year: 2017

Journal

Journal of The Electrochemical Society Electrochemical Society

Book Volume: 164

Pages Range: H734-H742

Journal Issue: 12

DOI: 10.1149/2.0351712jes

Abstract

The state was investigated of the copper surface in phosphate buffered saline (PBS; 140 mM Cl⁻, 10 mM phosphate; pH 7) by a combination of cyclic voltammetry (CV) and chronoamperometry (CA) with in situ spectroscopic ellipsometry and Raman spectroscopy. After polarization, samples were analyzed ex situ. In agreement with expectations on the basis of the Pourbaix diagram, Cu2O and Cu4O3 were observed when polarizing the system above ≈−0.05 V vs. Ag|AgCl|3M KCl. The formation of Cu2O did not lead to a passivation of the system. Rather, the system dissolved under formation of soluble square planar CuCl² 4 ⁻, identified by its strong Raman peak ≈300 cm⁻¹. During dissolution, spectroscopic ellipsometry showed a film with a stable steady state thickness. Energy electron loss spectroscopy (EELS) analysis of a cross section of the oxide after removal from the electrolyte showed that the oxide was Cu2O. It is suggested that Cl⁻ replaces oxygen vacancies in the oxide layer. As soon as oxidation to Cu^II becomes dominant, the dissolution proceeds to soluble Cu^II species. The outer surface of copper under these conditions is hence a Cu2O-like surface, with Cu^II complexes present in solution.

Involved external institutions

Max-Planck-Institut für Eisenforschung GmbH (MPIE) / Max Planck Institute for Iron Research

Germany (DE)

How to cite

APA:

Toparli, C., Hieke, S.W., Altin, A., Kasian, O., Scheu, C., & Erbe, A. (2017). State of the surface of antibacterial copper in phosphate buffered saline. Journal of The Electrochemical Society, 164(12), H734-H742. https://doi.org/10.1149/2.0351712jes

MLA:

Toparli, Cigdem, et al. "State of the surface of antibacterial copper in phosphate buffered saline." Journal of The Electrochemical Society 164.12 (2017): H734-H742.

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