Shortly after a surface is submerged in the sea, a conditioning film is generally formed by adsorption of organic molecules, such as polysaccharides. This could affect transport of molecules and ions between the seawater and the surface. An artificial seawater model system was developed to understand how adsorbed polysaccharides impact copper binding by glutaraldehyde-crosslinked polyethyleneimine coatings. Coating performance was also determined when competed against copper-chelating EDTA. Polysaccharide adsorption and copper binding and distribution were investigated using advanced analytical techniques, including depth-resolved time-of-flight secondary ion mass spectroscopy, grazing incidence X-ray absorption near-edge spectroscopy, quartz crystal microbalance with dissipation monitoring and X-ray photoelectron spectroscopy. In artificial seawater, the polysaccharides adsorbed in a swollen state that copper readily penetrated and the glutaraldehyde-polyethyleneimine coatings outcompeted EDTA for copper binding. Furthermore, the depth distribution of copper species was determined with nanometre precision. The results are highly relevant for copper-binding and copper-releasing materials in seawater.
Bibliographical noteFunding Information:
The project is supported by the Premier?s Research and Industry Fund grant provided by the South Australian Government Department of State Development. The authors acknowledge that work was performed at the South Australian node of the Australian National Fabrication Facility, a company established under the National Collaborative Research Infrastructure Strategy to provide nano- and micro-fabrication facilities for Australia?s researchers. They also acknowledge the assistance of: John Denman, of the Australian Microscopy & Microanalysis Research Facility at the South Australian Regional Facility, University of South Australia; Andreas Karydas, Mateusz Czyzycki, Alessandro Migliori, Werner Jark and Diane Eichert for support on the experimental chamber for X-ray spectrometry of the International Atomic Energy Agency (IAEA), which is operated in partnership at the X-ray fluorescence beamline at Elettra, for which travel funding was provided by the International Synchrotron Access Program (ISAP) managed by the Australian Synchrotron and funded by the Australian Government; and Peter Kappen and Chris Glover for the bulk XAS measurements undertaken on the X-ray absorption spectroscopy beamline at the Australian Synchrotron, Victoria, Australia.
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- biocidal metals
- copper chelation
- selective binding