Document Type

Theses, Ph.D


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Publication Details

Thesis submitted for the award of Doctor of Philosophy from the Dublin Institute of Technology, 2008.


This work focuses on the mechanism of silver dissolution for biomedical and hygienic coating applications. The research work began from the investigation of silver dissolution behaviour from pure silver and silver-platinum alloys in solutions with or without chloride using the technique of cyclic volammetry (CV). A zero resistance amperometry (ZRA) measurement was carried out to study the effect of platinum on the silver dissolution behaviour in 0.89%wt. NaCI solution. The mechanism of silver dissolution from pure silver and silver-platinum alloys in 0.89%wt. NaCI solution was proposed by an equivalent circuit model under the investigation of electrochemical impedance spectroscopy (EIS). It was found that the addition of platinum decreased the kinetics for silver oxidation observed by CV and EIS. Thin silver and silver-platinum alloy coatings on polymeric materials were formed using a sputter coater with an argon plasma source. Silver dissolution from the plasma coatings on the polymeric material showed a similar behaviour to bulk silver or silver-platinum alloys investigated by CV in 0.89%wt. NaCI solution. Novel polymeric composites containing silver nanoparticles were prepared by the reduction of AgNO3 with NaBH4 under the protection of polymers. The properties of the silver nanoparticle polymeric composites were characterized by UV-vis spectroscopy, X-ray diffraction technique, as well as Raman spectroscopy. Silver dissolution behaviour from the polymeric silver nanoparticle composite was investigated by CV in 0.89%wt. NaCI. The antibacterial activities against strains of E. coli (Gram-negative) and S. aureus (Gram-positive) of silver nano-particles polymeric composite were investigated. The Alamar Blue (AB) assay and the Neutral Red (NR) assay were employed to evaluate the cytotoxicity of the polymeric silver nanoparticle composite to A549 cells. The silver nanoparticles stabilized with PVA crosslinking with adpic acid showed high antibacterial activity without causing serious cytotoxicity.