Thesis Format
Integrated Article
Degree
Master of Science
Program
Chemistry
Supervisor
Hedberg, Yolanda
2nd Supervisor
Biesinger, Mark
Abstract
N-Heterocyclic Carbenes (NHCs) are robust organic compounds, functionalized for binding metals through their strong sigma (σ) bond. This can provide a connection between certain metals and a protective coating that prevents corrosion. An X-ray photoelectron spectroscopy (XPS) peak fitting model was developed for 1,3-diisopropyl benzoimidazolium (iPrNHC) and some of its derivates. This informative and reproducible XPS peak-fitting model aimed to provide a curve-fitting routine for most bulk NHCs whilst also accounting for adventitious carbon on the surface of the sample. Additionally, this peak model was applied to XPS data from an application of the iPrNHC deposited onto mild steel. The model will be verified by using Multivariate Curve Regression (MCR), which is a form of chemometrics used to verify large sets of data.
Summary for Lay Audience
Metals are fundamental to modern society. They are a big part of transportation and construction. One of the biggest problems is that most metals are unstable in oxygen-containing environments and therefore will readily oxidize. One of the most common metals used for infrastructure is iron. Iron will oxidize quite fast and form what is known as rust. Rust will deteriorate infrastructure and cost a lot to repair. Corrosion of metal infrastructure is a big problem. The global cost of corrosion is substantial, costing about USD 2.5 trillion. A solution that works to improve the issues caused by corrosion has been ongoing in investigations by the macro-team of the Carbon to Metal Coating Institute.
However, a universal solution to corrosion prevention has yet to be established. Funding from the Carbon to Metal Coating Institute has allowed several projects to be undertaken that investigate different methods to prevent corrosion. One such method employs a solution deposition procedure, where an organic molecule is deposited onto steel. This molecule then acts as a glue between a coating and steel. Detection of the organic molecule, otherwise known as an NHC, is done by a surface-sensitive technique called X-ray Photoelectron Spectroscopy (XPS). XPS is a popular technique used to quantify the outermost 5-10 nm of sample surfaces. Previous studies with NHC on gold surfaces lacked in-depth XPS quantification of the organic molecule as a monolayer on the surface. This thesis will delve deep into the quantification of the bulk NHC powder (iPrNHC in its precursor form), and then apply this to mild steel surfaces.
To interpret and use its data correctly, a peak-fitting model was developed and used within this thesis to provide the most detailed quantification of NHC on the surface. Future studies look to verify the peak fitting model with chemometrics which is an advanced statistical analysis technique used to analyze large datasets.
Recommended Citation
Kaur, Ekrupe, "Developing Curve Fitting Procedure using X-ray Photoelectron Spectroscopy for N-Heterocyclic Carbenes" (2024). Electronic Thesis and Dissertation Repository. 10056.
https://ir.lib.uwo.ca/etd/10056