Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/192957

Title

Effect of gold oxide in measurements of colloidal force

Author(s)

Tabor, Rico F.;  Morfa, Anthony J.;  Grieser, Franz;  Chan, Derek Y. C.;  Dagastine, Raymond R.

Abstract

Atomic force microscopy, contact-angle, and spectroscopic ellipsometry measurements were employed to investigate the presence and properties of gold oxide on the surface of gold metal. It was found that, in agreement with available literature, unoxidized gold surfaces were hydrophobic, whereas oxidation rendered the surface highly hydrophilic. The oxide could be removed with ethanol or base but appeared to be stable over long periods in water or salt solutions between pH 3 and 7. After oxidation, the oxide layer thickness, determined using ellipsometry, was consistent with an approximate monolayer of Au-O bonds at the gold surface. The presence of gold oxide was found to alter significantly the electrical double-layer characteristics of the gold surface below pH 6 and may explain the apparent inconsistencies in observed force behavior where gold is employed as well as aiding in design of future microfluidic systems which incorporate gold as a coating.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Life and Social Sciences

Source

Langmuir, Vol. 27, no. 10 (May 2011), pp. 6026-6030

Publication year

2011

FOR Code(s)

0306 Physical Chemistry (Incl. Structural);  0903 Biomedical Engineering;  0904 Chemical Engineering

Keyword(s)

Atomic force microscopy;  Colloidal force;  Gold oxide;  Gold surfaces;  Oxidation

Publisher

American Chemical Society

ISSN

0743-7463

Publisher URL

http://dx.doi.org/10.1021/la200166r

Copyright

Copyright © 2011 American Chemical Society.

Peer reviewed