Plastics or polymers are thought to behave oppositely from metals. Ideally, polymers behave as insulators while metals conduct electricity. Shirakawa and coworkers discovered conductive polymers in 1977.1 These conductor polymers have been extensively studied, discovering that charge transfer oxidative doping of polyacteylene could increase its conductivity by 12 orders of magnitude. Polyacetylene, although showing promise as an organic conductor, because it is highly air-sensitive and oxidizes when exposed to molecular oxygen, therefore making this an unattractive use for commercial products. Attention has been focused on heterocylic aromatic polymers such as polythiophene and polypyrrole, in efforts to produce conductive polymers that are air-stable, tractable, and have a low band gap. The lone-pair electrons of the sulfur and nitrogen atoms tend to stabilize the positive charges of the p-doped polymers through resonance. 2 By using Shirakawas’ idea of using polypyrrole as the focus point of our research and expanding upon that by the addition of a rhenium metal to an organic compound, (1,2-C5H3(CNR)2) and this should offer some new and interesting chemical properties. These new properties are; new optical properties, new electronic properties, improved physical properties, and a reversible electrochemical shift. This research will help in the field of organometallic semiconductors in applications such as OLED’s, and electrochromic windows.3-6

<p>This thesis investigates the structure and ion mobility properties within the phosphate and fluorophosphate family of cathode materials for Li ion batteries using solid-state NMR. Developments in lithium ion battery technology are now directed towards automotive applications meaning that many of the cost and safety issues associated with current lithium ion battery technology need to be addressed. Within the current systems the high cost is largely attributed to the use of LiCoO₂ as the positive electrode. Many new and inexpensive Li intercalation materials have been put forward as alternatives to LiCoO₂, however the details concerning the structural and ion-transport properties of these new phases are not well defined. ^6,7Li, ³¹P, and ¹⁹F NMR measurements are an ideal tool to study these properties, as ^6,7Li is able to probe the local environment and dynamics of the mobile ion while ³¹P and ¹⁹F monitor changes in the host framework. Materials selected for study in this thesis include olivine LiFePO₄, monoclinic Li₃M₂(PO₄)₃ (M = V, Fe), the tavorite-based Li₂VPO₄F and Li₂VOPO₄, and the novel layered Li₅V(PO₄)₂F₂. The fluorophosphates have been introduced as higher voltage cathode materials for lithium batteries, however our ^6,7Li 1D selective inversion and 2D EXSY measurements reveal timescales of ion hopping that are relatively slow when compared to those measured in the phosphates. This indicates that the improved power output from the voltage gains may be lost to slow charge/discharge rates.</p> / Doctor of Philosophy (PhD)

<p>Differences in the wavelengths of the surface plasmon band of gold nanoparticles (AuNP) – before and after particle aggregation – are widely used in bioanalytical assays. However, the gold surfaces in such bioassays can suffer from exchange and desorption of non-covalently bound ligands and from non-specific adsorption of bio-molecules. Silica shells on the surfaces of the gold can extend the available surface chemistries for bioconjugation and potentially avoid these issues. Therefore, silica was grown on gold surfaces primed with polyvinylpyrrolidone (PVP) using either hydrolysis/condensation of tetraethyl orthosilicate under basic conditions or diglycerylsilane at neutral pH. The former precursor permitted slow, controlled growth of shells from about 1.7 to 4.3 nm thickness. By contrast, silica shells formed within an hour using diglyceroxysilane; the thickness was insensitive to changes in silane concentration and incubation time and could be tuned using different molecular weight PVP to prime the particles. The control over shell thickness is discussed with respect to the PVP interface, the electrical double layer, and interpenetrating organic-inorganic hybrid structures. Within the range of shell thicknesses synthesized, the presence of a silica shell on the gold nanoparticles did not significantly affect the absorbance maximum (~ 5 nm) of unaggregated particles. However, the change in absorbance wavelength upon aggregation of the particles was highly dependent on the thickness of the shell. With silica shells coating the AuNP, there was a significant decrease in the absorbance maximum of the aggregated particles, from ~578 to ~536 nm, as the shell thicknesses increased from ~1.7 to ~4.3 nm, due to increased distance between adjacent gold cores. These studies provide guidance for the iv development of colorimetric assays using silica coated AuNP. Such particles also show potential for application in 2D and 3D nanostructured assemblies.</p> / Master of Science (MSc)

<p>Lithium-ion batteries provide a more cost-effective and non-toxic source of reusable energy compare to other energy sources. Several research studies have lead to production of some more promising cathode components for lithium ion batteries. Recently, a new series of pyrophosphate-based composition Li₂FeP₂O₇ and Li₂MnP₂O₇ has been reported as cathode materials. They have shown a 3D framework structure and the two Lithium-ions in the three-dimensional tunnel structure make it possible that more than one lithium ion be extracted during cycling. Lithium solid state nuclear magnetic resonance (NMR) is an effective technique to study this cathode material, not only for analyzing local structure, but also for investigation of the microscopic processes that take place in the battery.</p> <p>In this work, Li₂FeP₂O₇ and Li₂MnP₂O₇ have been synthesized. The lithium environment of these materials is studied using 1D ^6,7Li NMR. Assignment of Li₂MnP₂O₇ spectrum has been made based on Fermi-contact interaction and crystal structure. Both variable temperature experiment and 1D selective inversion NMR are used to establish Li-ion pathways as well as Li hopping rates for Li₂MnP₂O₇. Also, ⁷Li MAS NMR measurements are used to characterize Li environments in LixFeP₂O₇after being electrochemically cycled to different points, and preliminary results regard to changes to ion mobility in LixFeP₂O₇at different electrochemical cycled points are presents here, solid-solution (de)lithetiation process is confirmed for this material.</p> / Master of Science (MSc)

<p>Silicone polymers, particularly PDMS (poly(dimethylsiloxane)) exhibit a wide range of exceptional properties including optical transparency, biostability, hydrophobicity and excellent oxygen transmissibility that make them extremely useful in a wide range of applications, particularly as biomaterials. Current methods for the preparation of silicone elastomers have been well documented, however, silicone elastomers are thermoset materials and once cured, they cannot be reformed without chemical intervention. The properties of silicones that make them a popular material choice in a wide variety of industries also make them un-responsive and non-reusable often limiting their application to one primary purpose.</p> <p>This thesis aims to further understand the mechanisms of silicone polymer chain interactions and how the chemistry of polymer modification can alter the mechanical and chemical properties of materials. The effects of distinctive functional groups (coumarin) on silicone chains to allow for both the formation of thermoplastic silicone elastomers and stimuli-responsive elastomers for reversible crosslinking are explored.</p> <p>A companion study examined a different way to form silicone elastomers. The Piers- Rubinsztajn reaction was used to create elastomers and foams rapidly and under relatively mild conditions using very small quantities of the catalyst B(C6F5)3. The factors required to create – on demand – a foam or an elastomer, and the strategies to control physical properties, including bubble density and modulus, are explored.</p> <p>Silicone foams that were structured in a completely different way are described. Allyl- modified PEG (poly(ethylene glycol)) was found to structure foam mixtures precure. The product foam after cure was amphiphilic, due to the presence of both silicone and PEG constituents. The origins of bubble stabilization and the ability to control foam properties are described.</p> / Doctor of Science (PhD)

<p>The development of both silica and silicones has led to enormous improvements in available products over the last 50 years: the compounds have now found practical applications in fields ranging from electronics to biomaterials. Both of these materials have several desirable intrinsic properties. The compounds can be combined as a blend, in a composite or at an interface with other compounds to tune the chemical and physical properties to those desired. On their own, silica and silicones also have many applications. Their utility would be enhanced if it was possible to improve morphological control of the materials independently or together.</p> <p>This thesis explores various parameters and factors that enable the structuring of elastomers, colloids/suspensions, films and foams with the use of unconventional or new organosilicon chemistries. Specifically, amine and boron based catalysts are utilized to catalyze silicone and silica formation at different interfaces to create the materials mentioned above. Potential applications for these materials include drug delivery, GC chromatography and paper-based diagnostics.</p> / Doctor of Philosophy (PhD)

Self-assembly of colloidal microparticles is one of the strategies for making characteristic patterns. These versatile self-assemblies provide a route to elevate the efficiency of an electronic device. Silsesquioxane particles with various functionalities were synthesized by a modified Stöber condensation method. This thesis describes the synthesis of benzylchloride silsesquioxanes, benzylchloride-amine silsesquioxanes and amine-functionalized silsesquioxane particles with multi-fluorescent tags. The size and morphology of the particles were controlled by varying the concentration of base and anhydrous ethanol (solvent). The size distribution of particles was controlled by adjusting the molar ratios of organotrialkoxy silane, base, and ethanol concentrations. Through selective post-functionalization with fused arenes of anthracene and rhodamine, multifluorescent particles were obtained. Morphologies and optical properties of particles were characterized by TEM, SEM, fluorescence optical microscopy, and absorption and fluorescence spectroscopies. The composition of silsesquioxanes was confirmed by FTIR, thermogravimetric analysis, and elemental analysis. A versatile technique was developed for the self-assembly of particles on different polymer substrates by changing the colloidal suspension concentration and the polymer substrate.

This research explores the synthesis of anthracene and stilbene-based metal-organic framework (MOF) structures as potential scintillating (radioluminescent) materials for use in the detection of gamma radiation. The organic molecules 9,10-anthracenedicarboxylic acid (ADCH2) and trans-4,4’-stilbenedicarboxylic acid (SDCH2), were each used as a linker, in combination with a range of lanthanide metal ions, to synthesize novel three dimensional MOF structures under hydrothermal conditions. With ADCH2, the early period lanthanides yield isostructures with the metal ion in higher coordination (nine) than for those with late period metals (seven). The ADC-MOFs show linker-based photoluminescence properties with well defined vibronic peaks in their emission profile and their emission (λmax~435 nm) blue shifting from that of the ADCH2 powder (~500 nm) and closer to the organic molecule in monomer arrangement (λmax ~ 420 nm). The structures also show photoluminescence lifetimes between 1 and 2 ns, which is similar to the reported value for monomeric anthracene units. The blue-shift and reduction in lifetime, compared to ADCH2, are indicative of minimal π-π interactions amongst the aromatic moieties, thereby limiting the non-radiative relaxation pathways. On exposure to ionizing radiation (protons and g- rays), the ADC-MOFs demonstrated scintillation properties, with a radioluminescence lifetime of ~ 6 ns which is similar to that of the ADCH2 powder. A combination of SDCH2 and lanthanide metal ions produced two isostructured MOFs containing Tm3+ and Er3+, under the hydrothermal synthesis conditions explored. The 3-D structure contained ultra large diamond-shaped pores with dimensions of 16 Å x 30 Å. A blue-shift of fluorescence spectra was observed for the SDC-MOF structures (λmax ~ 425 nm) compared to that of bulk SDCH2 powder (λmax ~475 nm), and closely resembling that of monomeric isolated SDC units (λmax~475 nm). Their photoluminescence lifetime is ~0.76 ns, about half of that observed for SDCH2 powder. The blue shift and reduction in lifetime (compared to SDCH2) is attributed to minimal π-π interactions between SDC units in the MOF structure, thus minimizing associated non-radiative relaxation pathways. The isolation of anthracene and stilbene in MOF structures therefore has the potential to improve their performance as scintillators.

Two novel materials have been developed: TiO2/poly(dimethylsiloxane) (PDMS) beads as buoyant photocatalyst materials for water remediation, and copper rhodamine‑B silane (Cu‑RBS) as an n ‑type organic/inorganic hybrid for thermoelectric applications. The approach to incorporate TiO2 into low‑density PDMS beads addresses many of the challenges traditionally encountered when creating buoyant photocatalysts, an area which is crucial for wide‑spread remediation of water resources, including natural bodies of water. The performance and reusability of the buoyant photocatalyst materials, demonstrated by using methylene blue as a model degradation target, is strong enough for environmental application. The use of a kinetic model and the introduction of a parameter to allow comparison of buoyant photocatalysts is also included as part of the analysis. The performance of Cu‑RBS was investigated as a low‑temperature thermoelectric material. Clear improvements in the electrical conductivity and Seebeck coefficient are observed for RBS upon coordination to Cu2+. Evidence explaining this improvement is provided by computational analysis and by concentration‑dependent optical absorption and fluorescent emission measurements, all of which indicate that a metal‑to‑ligand charge transfer occurs from Cu2+ to RBS. Although the power factor of Cu‑RBS is low compared to other materials reported in the literature, these results provide a promising approach to increasing both the Seebeck coefficient and electrical conductivity of n‑type small molecule organic systems.

In recent years, research has focused on reducing the cost of catalysts in a variety of ways including using less expensive materials, improving the synthetic method, and increasing the catalytic activity, recovery, and recyclability. Typically with nanoparticles, the size, shape, composition, and surface coating have an effect on catalytic activity.1-2 In this work, we focused on reducing the cost of precious metal based catalysts by altering the synthetic methods. One way to lower the cost of synthesizing precious metal nanoparticles is by debasing the precious metal with a second cheaper more abundant metal. CuPd nanoparticles were synthesized in oleylamine and displayed catalytic activity in several cross-coupling reactions. Due to copper being present in the nanoparticle, a copper halide co-catalyst was not needed for Sonogashira cross coupling to be successful.3 While this method produced reactive catalysts, low product yield hinders its application for industry. Solution based synthesis of metallic nanoparticles typically require long reaction times and high temperatures, which make large scale production of nanoparticles on an industrial scale difficult.4-5 The use of continuous flow microreactors provides greater control of synthetic parameters, leading to lower batch-to-batch variability and increasing the efficient of heat and mass transfer and have been applied to the synthesis of metals, semiconductors, zeolites, organic compounds, and semiconductors.5-7 To compare continuous flow methods to benchtop reactions, a well-characterized benchtop reaction synthesizing Cu@Ni core/shell nanoparticles was successfully transferred to a flow reactor set-up. Cu@Ni nanoparticles were synthesized using a capillary microreactor in under 1 minute compared to the 1 hour reaction on benchtop with similar properties in a green solvent.2 The Cu@Ni nanocomposites were active towards the Fischer Tropsch reaction.8 2 nm platinum nanoparticles and platinum bimetallic alloys were synthesized in water using a capillary microwave flow reactor. Investigations showed the nanoparticles were activity toward hydrogenation of octene. With further development, continuous flow synthesis of metallic nanoparticles can be applied to the synthesis of a wide variety of catalysts on an industrial scale. Continuous flow methods provide greater control of reaction parameters, increased safety by reacting smaller volumes of chemicals at a given time, and decreasing the batch-to-batch variability.