Thesis Format
Integrated Article
Degree
Master of Science
Program
Chemistry
Supervisor
Ragogna, Paul J.
2nd Supervisor
Gilroy, Joe B.
Co-Supervisor
Abstract
The corrosion of infrastructure costs Canadians billions of dollars annually and can be combatted using anti-corrosion coatings. This thesis describes the synthesis and surface deposition of polystyrenyl N-heterocyclic carbenes (NHCs) for use in metal protection, as well as the effects of cross-linking on film performance. Chapter two outlines the syntheses of styrenyl NHC precursors, and NHC-Au complexes to demonstrate their utility as ligands. Chapter three examines methods towards NHC deposition, and film formation is confirmed using surface analysis techniques. After immersion deposition and on-surface polymerization on gold substrates, NHC films show partial passivation of the metal surface. The electrodeposition of NHCs involves a simultaneous deposition and polymerization process, and the resulting polymeric films exhibit excellent protection properties. Electrochemical studies show improved passivation and charge transfer resistance of the cross-linked film compared to the linear polymer, which together demonstrate the increased corrosion resistance of cross-linked poly(NHC) coatings.
Summary for Lay Audience
The degradation of large-scale infrastructure in Canada costs Canadians billions of dollars per year, and poses massive safety and environmental health risks. This deterioration often takes the form of corrosion, which turns metals into compounds called metal oxides. A common example of corrosion is rusting, through which iron metal is converted into iron oxides, and the resulting rust exhibits poor structural integrity and flaking. Anti-corrosion coatings, such as paints, are often used to combat the degradation of metals, and typically include polymers for their protection abilities. Polymers are chains of repeating units that form extremely large molecules and are used in anti- corrosion coatings for their water resistance and stability. Polystyrene, also called StyrofoamTM, is a well-known polymeric material composed of styrene repeating units, and imparts excellent corrosion resistance to paints and other coatings. However, polystyrene-based coatings exhibit limited adhesion to metal surfaces due to its non-reactive chemical structure and benefits from the addition of “adhesive” molecules to act as anchors. This thesis targets the use of cyclic nitrogen-containing molecules called N-heterocyclic carbenes (NHCs) for use as surface anchors. NHCs contain a carbene functional group, which is a very reactive carbon center, and can be easily modified to exhibit different substituents, including styrene. In this work, styrene-containing NHC films were formed on gold surfaces through various methods, and polymerization experiments were performed to create polymeric NHC coatings. The polymerized NHC films demonstrated excellent metal protection and stability, and have promise for use in anti-corrosion applications.
Recommended Citation
Bosso, Jessica L., "Polystyrene-Functionalized N-Heterocyclic Carbenes as Anti-Corrosion Coatings" (2024). Electronic Thesis and Dissertation Repository. 10204.
https://ir.lib.uwo.ca/etd/10204
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.