Electrochemical cycling of Ag surfaces under basic conditions has led to the discovery of a new, simple, rapid and cost effective method for the preparation of nano-structured Ag surfaces with features ranging from 30–150 nm in diameter. Our results indicated that during cyclic voltammetry, the surface was oxidized, resulting in the formation of soluble Ag complexes which were re-deposited as elemental Ag nanostructures (NSs) on the cathodic scan. The electrochemical properties of the Ag NSs were greatly affected by the presence of organophosphonates and other additives (vide infra), which also influenced the growth of nanostructures. The interaction of these Ag NSs with malathion and paraoxon were explored in more detail using Surface Enhanced Raman Spectroscopy. Results showed that generally smaller nanosized features resulted in high quality surface Raman enhancement. Next, Ag NSs’ properties in the presence of organophosphonates was investigated in tap water and apple juice in order to address issues related to matrix effects and potential interference from constituents in solution. Electrochemical and localized surface plasmon resonance results demonstrated the ability to detect organophosphonates in real samples, albeit at a lower limit of detections and without any selectivity to any particular organophosphonate. Next, the morphology and corrosion behaviour of Ag surfaces was explored in the absence and presence of surfactants and capping agents. Results demonstrated the protection of Ag surfaces against corrosion in the presence of Tween-20, while potassium citrate presence enhanceed corrosion of silver surfaces, resulting in the formation of a pitted surface with smaller Ag NSs. Lastly, the interactions of 2-cyano-3-(2′-(5′,10′,15′,20-tetraphenyl porphyrinato zinc-(II))yl) acrylic acid-modified Ag NSs with biomolecules were explored using spectro-electrochemical techniques. The photocurrent response of porphyrin-modified Ag NSs was quenched by the addition of adenosine-5’-monophosphate (AMP), guanosine-5’-monophosphate (GMP) and cytidine5’-monophosphate (CMP), with a quenching efficiency of 80%, 68% and 48% for AMP, CMP and GMP, respectively.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/43443 |
| Date | 20 December 2013 |
| Creators | Fathi, Farkhondeh |
| Contributors | Kraatz, Heinz-Bernhard |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis, Dataset, Image |
Page generated in 0.0019 seconds