The Diels-Alder dimerization of trans-1-substituted butadienes is expected to yield a cyclohexene adduct with the substituents in the 3 and 4 positions cis to one another. This prediction is based on past observations of other Diels-Alder additions. The cis-isomer is the only one consistent with a two-stage mechanism proposed by Woodward and Katz. In the case of trans-phenylbutadiene, the expected adduct is cis-3-phenyl 1-4-(trans-styry1) cyclohexene. Alder, Haydn and Vogt, however, reported that the corresponding trans-isomer is the dimerization product. There is reason to believe that the observation of the trans-isomer may have been the result of product isomerization during purification. In view of the unexpected nature of the product and its implications with respect to the Diels-Alder mechanism, the dimerization reaction was reinvestigated. trans-Phenylbutadiene was heated at 1300 for six hours. Analysis by thin layer chromatography on silica gel impregnated with silver nitrate revealed two major components as well as several minor ones. The two major components were isolated by column chromatography on silica gel impregnated with silver nitrate. They were present in roughly equal proportions. One of them was purified and found to be identical with cis-3-pheny l~4-(trans-styry l) cyclohexene prepared by an independent method. The second major component, not yet isolated in pure form, is probably the corresponding trans-isomer on the basis of IR and NMR spectra as well as the fact that the trans-isomer was found by Alder et al. An evaluation of the significance of this reaction with respect to the Diels-Alder mechanism will have to await positive identification of the second component as well as a more careful determination of its relative proportion to the cis-isomer.

Oxygen reduction reaction (ORR) has considerable potential for the pro-duction of electricity, issues with water splitting and many other applications in the energy sector. But in order to increase the efficiency of the reaction an electrocatalyst needs to be introduced. In today’s industrial devices precious and costly metals such as platinum (Pt) are used as catalysts. Other more abundant and cheaper alternatives, for example cobalt oxides, are therefore being investigated. In this thesis, pure cobalt (Co) thin films were synthesised to investigate if thin films can be used for the catalysis of ORR. This was successfully carried out by electrochemically modifying the thin films and grow catalytically ac-tive hexagonal cobalt oxide nanoparticles.   Multicomponent system CoCrFeNi is an emerging alloy system with high research interest for its high corrosion resistance suitable for harsh environments in which the applications for ORR are found. In this thesis, CoCrFexNi were synthesised as thin films. The corrosion resistance of the films was investigated in addition to their catalytic activity. The effect of Fe content on these properties was also studied. The presence of Fe was crucial for the electrochemical activation of films and catalytic activity towards ORR.  In summary, this thesis shows that cobalt based thin films can be used as catalysts combined with corrosion resistance for ORR applications.

Several fluorenone alkynyl based oligo conjugated molecules were synthesized and characterized. Most compounds exhibited UV-Vis absorption onset at ca. 500 nm and a PL emission onset of ~329-370 nm, with excimer emission suspected from most systems near ~530-560 nm. Experimentally determined EHOMO and ELUMO energies range from -6.02 to -5.73 eV and -3.47 and 3.55 eV, respectively, with the lowest experimental Eg lying at -2.26 eV for 2-(trimethoxyphenylacetylene)-fluorenone. Cyclic voltammetry indicates quasi-reversible reduction for all systems, with 2,7-bis(nitrophenylacetylene)fluorenone exhibiting a high reduction potential of -1.25 eV. Only 2,7-bis(trimethoxyphenylacetylene)fluorenone exhibited a quasi-reversible oxidation, due to electron rich methoxy substituents. Diketopyrrolopyrrole systems as electron acceptors were also explored.

Liquid based electrolytes are known to have safety issues and for their low volumetric energy densities to meet the future energy storage demand. Solid electrolytes based on ion conducting solid ceramic and solid polymer electrolytes are being studied and considered as an alternative to alleviate the issues with liquid electrolytes. Their mechanical property to better suppress dendrite formation gives them an edge to be considered in the realization of high - capacity lithium metal batteries. However, each have such issues associated with them as low ionic conductivity in the case of polymer electrolytes and bad interfacial contact with the lithium anode in the case of inorganic ionic conducting solid electrolytes. Polymer – ceramic composite electrolytes are regarded as a promising option to take advantage of the merits of both and obtain a solid electrolyte which can conduct lithium ions as high as in the mS/cm scale with good electrode – electrolyte interfacial contact, a high electrochemical stability window and high lithium dendrite suppression. This work has aimed to tune the surface of the garnet type ceramic electrolyte, Li7La3Zr2O7, referred to as LLZO, by acid treatment to bring about a better conductivity and lithium – ion transference number of the composite it is applied to. The acid, oxalic acid in this work, treatment has produced the required surface groups, hydroxide ion and oxalate ion, which are hypothesised to help improve the conductivity through the beneficial interactions they bring into the matrix. The conductivity and transference number measurements have revealed the treatment of the LLZO with the acid to have a positive impact on the conductivity and lithium – ion transference number of the composite compared to the untreated counterpart. Typical of the results obtained are the increment in conductivity and the lithium-ion transference number of composites containing 50 % ceramic (LLZO) mass loading. Across all the temperatures the conductivity is measured, an increment by a range of 2.5 times (at room temperature) to 7.8 times (at 60 0C) was obtained. Similarly, the lithium-ion transference number has increased from 0.121 in the composite containing 50 % untreated (pristine) LLZO to 0.159 in the composite containing the same mass loading of oxalic acid treated LLZO.

Phosphotungstic acid H3[PMo12O40](PTA) with the Keggin structure has become well known as a solid superacid with pKa≈-13. Such a strong acidity is caused by delocalization of the negative charge of the anion on many oxygen atoms over the surface of the Keggin structure. High acidity of PTA and its good solubility in water and other polar solvents enables its use as a highly active homogeneous catalyst. However, in spite of relatively higher reaction rate, homogeneous catalysis has various drawbacks that limit its practical application. The main drawback is the difficult and expensive removal of the used catalyst from the reaction mixture and its recycling. PTA also demonstrated good catalytic activity as a heterogeneous catalyst of various organic reactions, e.g. hydrolysis, hydration and polymerization. Wide application of a pure superacid in catalysis is limited by its low surface area and solubility in polar solvents. The objective of this work is the synthesis and study of insoluble superacidic catalysts covalently embedded into the silica matrix. The catalyst PTA/SiO2 was synthesized by the sol-gel method. Tetraethoxysilane was co-condensed with PTA in acidic media in the presence of Pluronic P123 surfactant as a pore-forming agent. The obtained gel was air-dried and calcined at 500 °C producing a mesoporous material with a significant fraction of micropores in its structure. Isotherms of adsorption/desorption of nitrogen indicated cylindrical shape of the pores with necks that is typical for materials obtained with Pluronic P123 as a template. Cs-exchanged material was prepared by mixing PTA/SiO2 with a solution of CsCl. The cation exchange on cesium decreased the total pore volume due to a much higher volume of cesium ions as compared to protons. In addition, partial pore blocking by these ions restricted access to small pores thus reducing accessible surface area. Heteropolyacids are unstable in alkaline media that makes direct solid-state titration impossible. Surface acidity of the samples was determined by reversed titration. Dry samples were dispersed in a solution of pyridine in tetrahydrofuran. After equilibration, the solid phase was filtered, and the filtrate was titrated by HCl. PTA/SiO2 has a very high adsorption capacity on pyridine, which corresponds to 15 molecules of pyridine per [PMo12O40]3- anion. This number exceeded the number of available protons. The catalysts were successfully tested in the alkylation of mesitylene by alkenes. The use of superacidic materials in catalytic reactions can significantly improve the effectiveness of the processes.

The field of organic solar cells is getting more and more attention as the need forrenewable energy sources rises. When developing new materials for organic solar cellssynthesizing the new materials, is a time consuming and costly process. Therefore acomputational model for predicting how effective a new material, is without the needfor synthesizing. In this thesis an attempt to create a model for predicting open circuitvoltage in organic solar cells. Descriptors was calculated using B3LYP/6-31G hybridfunctionals. By creating a data set of donor and acceptor molecules with known andunknown open circuit voltage, and empirically trying to find a correlation between thedata sets that can be extrapolated and modeled. The results of this thesis did notmeet the goal of creating a model for predicting the open circuit voltage. Where nosignificant correlation was found, due a to small sample size.

This project involves the fabrication and testing of microporous, polymer membranes designed to remove minute amounts of toxic air pollutants such as formaldehyde from air streams. The hypothesis to be tested is that active, the silver contained within the porous polymer membranes results in high formaldehyde retention. Monolayers consist of different sizes of sPS particles are assembled first on the silicon wafers by spin coating method and convective assembly method, respectively. Then each kind of monolayer with one dimension of sPS particles is deposited with a nanometer scaled silver thin film with a bench top metal evaporator. The porous membranes are produced by assembly of close-packed colloidal crystals of silver capped polystyrene template particles and subsequent infiltration with polyurethane prepolymer. The prepolymer is cured by UV exposure. The sPS particles are removed from the particle polymer membrane by treatment with organic solvents resulting in the formation of inverse opal structures. Silver does not dissolve in the organic solvents and cannot leave the pores due to the small size of connecting holes in an inverse opal. All the monolayers, cylindrical colloidal crystals and microcapillaries after infiltration of polyurethane had been characterized by optical microscope, and the porous membranes had been characterized by SEM. The application of porous membranes with silver caps is to absorb formaldehyde in the air, while in fact the silver caps are oxidized and become Ag2O, which will initiate a gas-phase/solid reaction with formaldehyde. In the future, TiO2 will be applied together with Ag2O, since TiO2 is another good absorbent for formaldehyde

Eight fluorescent indicators were evaluated for their ability to detect the corrosion of aluminum metal substrates. The fluorophore Rhodamine-salicylaldehyde (RSA) was selected as a candidate for further study based on its ability to bind and detect aluminum ions at low concentrations, its selectivity for aluminum ions, its long-term stability, its solubility in our solvent-based epoxy formulation, and its compatibility with our testing method. A recent publication suggested that an alternative method of fluorescence activation was possible—an acid-promoted ring opening that occurred in the absence of metal ions. To prove the capability of RSA to bind aluminum ions, thorough 1H and 27Al nuclear magnetic resonance spectroscopy, mass spectrometry, and fluorescence analysis was conducted. It was found that RSA bound aluminum ions, with a preferred binding stoichiometry of 2:1 RSA/Al. Long-term immersion and salt spray corrosion studies were conducted to investigate the ability of RSA to detect corrosion on aluminum substrates. Aluminum panels were coated with epoxy coatings that contained the fluorescent indicator. Following optimization, a linear relationship between corroded area and time of immersion/exposure to salt fog was observed.

The goal of this thesis was to design thermally responsive polyol resins that would be compatible with isocyanates. Two approaches were made to reach this goal, the first involved functionalizing soybean oil and the second involved post-polymerization modification of a methacrylate based resin. A soybean based coating with thermally responsive Diels-Alder linkages has been prepared following an automotive two-component formulation. The resulting coatings displayed the capability to be healed following physical deformation by a thermal stimulus, and such a material has significant potential for end users. Various curing agents were employed, and resulted in variation of scratch resistance and re-healablity. Different thermally responsive soybean resins were synthesized to have varying amounts of reversible and nonreversible linkages when incorporated into the coating. Additionally, different isocyanates were added at differing ratios of NCO:OH in search of the optimum coating. It was found through the analysis of re-healabilty, hardness, gloss, and adhesion that the optimal combination was an acetylated resin (no irreversible crosslinks) with 54% reversible Diels Alder linkages at an NCO:OH ratio of 5:1 using isophorone diiscocyanate. Materials were evaluated via differential scanning calorimetry (DSC), scratch resistance, Koenig hardness, gloss measurements, and topographical analysis. In the second project, copolymerization of methyl methacrylate and 2-isocyanatoethyl methacrylate via free radical polymerization was done to synthesize a polymer with pendant isocyanates. The isocyanate was used as a chemical handle to incorporate Diels-Alder linkages into the PMMA resin. The PMMA resin with Diels-Alder linkages was successfully synthesized and incorporated into a polyurethane gel as proven via 1H NMR and IR. The gel showed thermal reversibility at 120°C due to retro-DA reaction via DSC as well as thermally reversible bulk properties.

Ever since the advent of polymer science, polyurethanes have played a huge role in the industrial world. They have been used in endless applications from furniture padding to aircraft coatings, to binders for insensitive munitions. It is therefore important that the chemistry of polyurethanes is well understood as well as the ability to draw relationships between the raw materials selected and the end-use properties of the polymer. Because of the multitude of practical applications, the development of an undergraduate polymer chemistry laboratory focused on polyurethane elastomers is developed and described herein. Polymer chemistry students are exposed to hydroxyterminated polybutadiene (HTPB) polyols as well as di- and multifunctional isocyanates for use in a tin-catalyzed reaction. The effect of catalyst concentration and crosslinking agent on cure time, prepolymer structure on end-use properties, and the effect of crosslink density on physical properties are explored. Students also receive a very important introduction to statistical experimental design. They learn when using statistical experimental design is necessary, and they learn how to manipulate, analyze, and interpret data using two-way ANOVA in Minitab. The development of the lab experiment also led to extrapolating the use of polyurethane elastomers into a new application, the development of a polyurethane spinal muscular atrophy (SMA) brace. SMA is a neurodegenerative disorder that results in the mutation or deletion of the spinal motor neuron gene, resulting in the atrophy of a subject’s spine muscles throughout the continuation of their life. These patients are therefore forced to wear a brace for the entirety of their lives. The current brace technology in use by SMA patients is limited by the fact that SMA affects a very small amount of the population and therefore it is not cost-effective for industry to develop a brace technology designed for these patients. Scoliosis braces such as thoracolumbrosacral orthoses (TLSOs) are too hard and too uncomfortable for patients with SMA; therefore, the polyurethane elastomer was extrapolated to develop a brace with more flexibility and more durability. Two generations of polyurethane elastomeric brace were developed and evaluated by a subject and family with an SMA background. The brace is a much improved technology to the TLSO braces and provides more flexibility, more mobility, greater comfort, and superior modularity to the old technology. An instruction manual is also included with a step-by-step process of how to reproduce the brace.