In order to extend the applications of aluminium, organic coatings may be applied on sheet materials, for instance for corrosion protection or aesthetic surface finish purposes in the automotive and construction industries, or on foil materials in the flexible packaging industry. The most common mechanisms for deterioration and structural failure of organically coated aluminium structures are triggered by exposures to the surrounding environment. Despite the great importance to elucidate the influence of exposure parameters on a buried aluminium/polymer interface, there is still a lack of knowledge regarding the mechanisms that destabilise the structure. It is generally believed that a detailed in situ analysis of the transport of corroding species to the buried interface, or of surface processes occurring therein, is most difficult to perform at relevant climatic and real-time conditions. In this work, Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) in the Kretschmann-ATR configuration was successfully applied to in situ studies of the transport of water and ionic species through polymer films to the aluminium/polymer interface upon exposure to ultra pure deionised water and to a 1 M sodium thiocyanate (NaSCN) model electrolyte. Other main processes distinguished were the formation of corrosion products on the aluminium surface and swelling of the surface-near polymer network. Hence, in situ ATR-FTIR was capable to separate deterioration-related processes from each other. To perform more unambiguous interpretations, a spectro-electrochemical method was also developed for in situ studies of the buried aluminium/polymer interface by integrating the ATR-FTIR technique with a complementary acting technique, Electrical Impedance Spectroscopy (EIS). While transport of water and electrolyte through the polymer film to the aluminium/polymer interface and subsequent oxidation/corrosion of aluminium could be followed by ATR-FTIR, the protective properties of the polymer as well as of processes at the aluminium surface were simultaneously studied by EIS. The integrated set-up provided complementary information of the aluminium/polymer sample investigated, with ATR-FTIR being sensitive to the surface-near region and EIS being sensitive to the whole system. While oxidation/corrosion and delamination are difficult to distinguish by EIS, oxide formation could be confirmed by ATR-FTIR. Additionally, while delamination and polymer swelling may be difficult to separate with ATR-FTIR, EIS distinguished swelling of the polymer network and also identified ultimate failure as a result of delamination. The capability of the integrated ATR-FTIR / EIS in situ technique was explored by studying aluminium/polymer systems of varying characteristics. Differences in water and electrolyte ingress could be monitored, as well as metal corrosion, polymer swelling and delamination. / QC 20101124

A cation-responsive electrode system has been developed which incorporates aza-substituted crown ethers as ligands. In a novel application, uncomplexed crown ethers were used in the pelletized form for ionic transport. Electrodes have been produced which can be conditioned for a particular ion and following their use, be reconditioned and reused for other ions. Preparation method and lifetime studies are included. The responses of two crown ethers with plasticizers were evaluated for thirteen representative cations. The concentration range covered in each evaluation was 1 x 10-1 to 1 x 10-7 M. For those ions exhibiting Nernstian or near-Nernstian response, selectivity coefficients were derived.

This report discusses research involving the reactions of 2-arylprop-1-en-3-yltrimethyl ammonium iodides with sulfur nucleophiles and the useful synthetic applications of the adducts formed. The present work may be subdivided into four sections: 1) reactions of several 2-arylprop-1-en-3-yltrimethylammonium iodides with benzenethiol; 2) reactions of several 2-arylprop-1-en-3-yltrimethylammonium iodides with the sodium salt of benzenesulfinic acid; 3) reactions of several 2-arylprop-1-en-3-yltrimethylammonium iodides with 2-mercapto-1-methyl imidazole; and 4) oxidation of 2-aryl-3-phenylthio-1-propenes and 2-aryl-3-phenylsulfonyl-1-propenes using sodium perborate. This report outlines the experimental conditions and procedures responsible for the synthesis of these products; in addition, this report describes the physical properties, NMR and IR spectra of the compounds synthesized, as well as offers a possible mechanism for their formation. The classes of compounds synthesized include: 2-aryl-3-phenylthio-1-propenes; 2-aryl3-phenylsulfonyl-1-propenes; 3-(2-aryl-l-propenyl)2-(1-methylimidazoyl)thioethers; and 2-aryl-2-acetoxy-3-phenylsulfonyl-1-propanols. Recommendations are listed to suggest future research in this area.

<p>Magnetotactic bacteria (MTB) are ubiquitous, multi-phylogenetic bacteria that actively synthesize chains of magnetic, membrane bound; single domain magnetite (Fe₃O₄) or greigite (Fe₃S₄) crystals, termed magnetosomes in order to better navigate to their preferred chemical environment using the Earth’s magnetic field. Discovered in 1963, the field is now focused on understanding magnetosome chain formation and associated processes through genetic studies as well as analytical techniques such as Transmission Electron Microscopy (TEM) and Scanning Transmission X-ray Microscopy – X-ray Magnetic Circular Dichroism (STXM-XMCD).</p> <p>This thesis performed studies on <em>Candidatus Magnetovibrio blakemorei</em> strain MV-1 using STXM at the C 1s, O 1s, Ca 2p and Fe 2p edges. STXM-XMCD was used to determine the magnetism of individual magnetosomes and quantitatively determine magnetic properties such as the magnetic moment of individual chains. A sub-population of MV-1 cells was identified as having anomalous magnetic orientations of magnetosome sub-chains when separated spatial gaps. The frequency of this event and the underlying implications to magnetosome formation are discussed.</p> / Master of Science (MSc)

<p>A systematic investigation of Polyvinylamine (PVAm) as a strength-enhancing polymer for wet paper was undertaken through the development of a new test method that simulates the influence of polymers on fibre-fibre bonding in paper. Pairs of wet regenerated cellulose membranes were laminated using the paper strength-enhancing polymer as the lamination adhesive. The resulting laminates served as a physical model for fibre-fibre bonds in paper and the wet laminate strength was determined by ninety degree peeling experiments. Key experimental parameters and sources of error were identified.</p> <p>The mechanism of PVAm paper wet strength enhancement was explored by the wet cellulose delamination procedure. Initial results showed that PVAm was a poor wet adhesive for cellulose unless the cellulose was lightly oxidized. The adhesion was found to be a strong function of the concentration of amine and of the cellulose oxidation products. This led to the hypothesis that there are two mechanism in action; the first being the well-accepted electrostatic bonding theories and the second being covalent bond formation between acetal/hemi-acetals/aldehydes and the amine.</p> <p>A thorough investigation of the surface chemistry and morphology was conducted to confirm the hypothesis of covalent bond formation between aldehydes and amines. Oxidized regenerated cellulose was laminated with PVAm and the peeled surfaces analyzed by X-ray Photoelectron Spectroscopy (XPS). It was shown that the wet delamination force correlated to the acetal/hemi-acetal/alehyde surface concentration. It was concluded that the delamination force would be increased by a cumulative strengthening of both the cellulose surface and adhesive interface.</p> / Doctor of Philosophy (PhD)

Student success in chemistry has been linked to a wide range of factors. Some of these factors are familiar, easily quantified measures; colleges typically rely on factors like high school GPA and measures of aptitude to make admission decisions or set course prerequisites. Success in chemistry courses can be linked to these measures, and math aptitude scores in particular are often used as prerequisites for introductory chemistry courses. However, success in chemistry can also be affected by factors like motivation, peer interactions, sense of belonging, and metacognitive skill. Additionally, outcomes in chemistry and other STEM courses like math and physics have been repeatedly found to be inequitable. In Chapter I, background information relevant to the subsequent chapters will be discussed. In Chapter II, group quizzes were implemented as a collaborative learning tool in a large-lecture format first-semester organic chemistry classroom. Chapter III describes a multifaceted scholarship support program for chemistry, physics, and math majors. This program strove to support traditionally underrepresented groups in chemistry through several components, including a team-building course and mentorship. Heavy emphasis was placed on building a peer support network. In Chapter IV, confidence surveys were implemented to encourage student metacognitive monitoring. Student success and confidence were assessed through three scopes: as they pertained to the overall course, by exam, and by individual topic.

Grafenoxid (GO) ar en lovande kandidat som nano-tillsats i medicinska byggnadsstallningar for benregenerering. GO kan forbattra den biologiska kompatibiliteten och osteogena prestandan hos polymerbaserade byggstallningar, och ocksa vasentligt bidra till forbattringen av materialets mekaniska egenskaper. I detta arbete ympades nano-grafenoxid (nGO) kovalent pa ytan av poly (e-kaprolakton) (PCL) genom att fdrst modifiera polymerytan via aminolys. Med anvandning av 1,6-hexandiamin / isopropanol infordes fria amingrupper framgangsrikt pa PCL-ytan for efterfoljande immobilisering av nGO. En optimerad ympningsprocess utvecklades via en losningsmedelsassisterad metod med vatten som losningsmedel for att kovalent binda nGO pa ytan av PCL byggnadsstallningar. De initiala nGO koncentrationerna var 0,5 och 1 mg / ml. fourier-transform infrarodspektroskopi (FTIR) och termogravimetrisk analys (TGA) verifierade bindningen mellan de funktionella gruppema pa nGO och de fria aminema. Svepelektronmikroskopi (SEM) visade en homogen fordelning av nGO pa ytan av de porosa byggnadsstallningarna. De mekaniska testema som utfordes demonstrerade · en 50 och 21 % okning av kompressionsstyrkan :for byggnadsstallningarna ympade med de initiala nGO-koncentrationema pa 0,5 och 1 mg / ml. In vitro-mineraliseringstester visade bildandet av mineralfallningar pa ytan av byggnadsstallningama som okade i storlek med hogre nGO-halt. A ven nGO: s potential som nano-barare av ett antibiotikum studerades i detta arbete. Pa grund av sitt overflod av kemiska funktionaliteter kan nGO effektivt adsorbera foreningar genom olika sekundara interaktioner. I denna studie optimerades dessa sekundara interaktioner genom att reglera losningens pH for maximal adsorption av ciprofloxacin, ett bredspektrum antibiotikum som anvands vid behandling av osteomyelit. Ciprofloxacin befanns kunna adsorberas starkast i sin katjonform vid pH 5, dar 1t-1t elektron­donatoracceptor (EDA) -interaktioner dominerar. Sammanfattningsvis bekraftar de resultat som presenteras i detta arbete potentialen hos nGO som egenskapsforbattrare och lakemedelsbarare i applikationer inom vavnadsregenerering. / Graphene oxide (GO) is a promising candidate as nano-filler material in scaffolds for bone regeneration. It has been demonstrated to enhance the biological compatibility and osteogenic performance of polymer-based scaffolds, aside from its substantial contribution to the improvement of the material's mechanical properties. In this work, nano-graphene oxide (nGO) was covalently grafted to the surface of poly( e-caprolactone) (PCL) by first modifying the polymer surface via aminolysis. Using 1,6-hexanediamine/isopropanol, free amine groups were successfully introduced to the PCL surface for the subsequent immobilization of nGO. An optimized grafting pathway, which implements the solvent-assisted method and uses water as a solvent, was developed to covalently attach nGO using initial concentrations of 0.5 and 1 mg/mL. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) both verified the successful attachment of nGO through the free amines. Scanning electron microscopy (SEM) depicts a homogeneous dispersion of nGO over the polymer matrix. Mechanical tests were performed and demonstrate a 50 and 21 % increase in compressive strength for the scaffolds grafted using initial nGO concentrations of 0.5 and 1 mglmL. In vitro mineralization tests showed the formation of mineral precipitates on the surface of the scaffolds that increased in size with higher nGO content. The potential of nGO as a nano-carrier of an antibiotic drug was also explored in this work. As it comprises of an abundance of chemical functionalities, nGO is able to efficiently adsorb compounds through various secondary interactions. In this study, these secondary interactions were optimized by controlling the solution pH for the maximum adsorption of ciprofloxacin, a broad-spectrum antibiotic used in the treatment of osteomyelitis. Ciprofloxacin was found to be adsorbed most strongly in its cationic form at pH 5, in which 1t-1t electron-donor acceptor (EDA) interactions predominate. Overall, the results presented in this work validate the potential of nGO as nano-enhancer and drug carrier in tissue engineering scaffold applications.

Although gas and liquid chromatography have emerged as dominant separation techniques in environmental analytical chemistry, these methods do not allow for the concurrent analysis of chemically diverse groups of persistent organic pollutants (POPs). There are also a small number of compounds which are not easily amenable to either of these traditional separation techniques. The main objective of this thesis was to address these issues by demonstrating the applicability of packed column supercritical fluid chromatography (pSFC) coupled to mass spectrometry (MS) in various aspects of environmental chemistry. First, pSFC/MS analytical methods were developed for legacy POPs (PCDDs, PCDFs, and PCBs) as well as the emerging environmental contaminant Dechlorane Plus (DP), and issues relating to the ionization of target analytes when pSFC was coupled to MS were explored. Novel APPI and APCI reagents (fluorobenzene and triethylamine) were optimized and real samples (water and soil) were analyzed to demonstrate environmental applicability. The possibility of chiral and preparative scale pSFC separations was then demonstrated through the isolation and characterization of thermally labile hexabromocyclododecane (HBCDD) stereoisomers. The analytical pSFC separation of the α-, β-, and γ-HBCDD enantiomers as well as the δ and ε meso forms was shown to be superior to results obtained using a published LC method. Finally, technical mixtures of phosphorus flame retardants (RBDPP, BPA-BDPP, and DOPO; a group of related compounds which are challenging to analyze concurrently) were examined using multiple analytical techniques and pSFC was found to be the only method which facilitated the accurate determination of the components of all 3 mixtures. This thesis confirms the potential of pSFC/MS as a fast, green, and cost effective means of separating and analyzing environmental contaminants.

Molecular modeling, using both ab initio and semi-empirical methods has been undertaken for a series of dirhodium complexes in order to improve the understanding of the nature of the chemical bonding in this class of homogeneous catalysts. These complexes, with carboxylamidate and carboxylate ligands, are extremely functional metal catalysts used in the synthesis of pharmaceuticals and agrochemicals. The X-ray crystallography shows anomalies in the bond angles that have potential impact on understanding the catalysis. To resolve these issues, minimum energy structures of several examples (e.g. Rh2(NHCOCH3)4, Rh2(NHCOCH3)4NC, Rh2(CO2CH3)4, Rh2(CO2CH3)4NC, Rh2(CHO2)4, and Rh2(CHO2)4NC) were calculated using Hatree-Fock and Density Functional Theory/B3LYP with the LANL2DZ ECP (Rh), and cc-pVDZ (all other atoms) basis sets.

Conventional screening of potential drug candidates through wet lab affinity experiments using libraries of thousands of modified molecules is time and resource consuming, along with the fact that it contributes to the widening time gap between the discovery of disease-causing mutations and the implementation of resulting novel treatments. It is necessary to explore whether the preliminary use of high-throughput virtual screening (HTVS) software such as PyRx will curb both the time and money spent in discovering novel treatments for diseases such as congenital heart defects (CHDs). For example, AXIN2, a protein involved in a negative feedback loop inhibiting the Wnt/β-catenin signaling pathway important for cardiogenesis, has recently been associated with CHD. The loss-of-function mutation L10F on the tankyrase-binding domain of AXIN2 has been shown to upregulate the pathway by loss of inhibition ability, leading to the accumulation of intracellular β-catenin. In a different paper, however, AXIN2 has been shown to be stabilized using XAV-939, a small-molecule drug which targets tankyrase. PyRx and VMD will be used to modify the drug in order to increase its binding affinity to AXIN2, stabilizing the protein and reinstating its inhibitory property to treat CHDs. When used in adjunction to wet lab experiments, HTVS software may decrease costs and the time required to bring a potentially life-saving treatment into use.