Electrostatic interactions such as halogen bonding and pnictogen bonding interactions have gained a lot of interest in the field of crystal engineering and pharmaceutical science. In the first part of this thesis, we expand our knowledge on anion coordinated halogen bonded cocrystals by looking at a series of cocrystals made from 3-iodoethynyl pyridine and 3-iodoethynylbenzoic acid. We utilize the power of mechanochemistry to create the new cocrystals made with phosphonium salts and use multinuclear solid-state nuclear magnetic resonance spectroscopy and X-ray diffraction and characterize them. We found that mechanochemistry is a fast and powerful tool to explore and synthesize new halogen bonded cocrystals and ³¹P solid-state NMR is a rapid way to identify the formation of a cocrystal. In the second part, we look at the versatility of the pnictogen atom, specifically antimony, as a pnictogen bond donor and a halogen bond acceptor. We evaluate these electrostatic interactions with nuclear quadrupolar resonance and found that nuclear quadrupole resonance is a strong spectroscopy tool to probe these types of electrostatic interactions.

Particulate composites are widely used in many aerospace applications such as protective coatings, adhesives, or structural members of a body and their mechanical properties and behavior have gained increasing significance. The addition of modifiers such as alumina generally leads to improved mechanical properties. This addition also enables the non-invasive study of the load transfer between the particle and the matrix. Understanding the load transfer between the particulate and the matrix material is the first step to understanding the behavior and mechanical properties of the composite as a whole. In this work, samples with an isolated alumina particle embedded in an epoxy matrix were created to replicate the ideal assumptions for many particulate mechanics models. In separate experiments, both photo stimulated luminescent spectroscopy (PSLS) and synchrotron radiation were used to collect the spectral emission and diffraction rings, respectively, from the mechanically loaded samples. The PSLS data and XRD data are shown to be in qualitative agreement that as particle size is increased, the load transferred to the particle also increased for the range of particle sizes tested. This trend of increasing load transfer with increasing particle size is compared with the classical Eshelby model. Results from this work provide experimental insight into the load transfer properties of particulate composites and can serve to experimentally validate the theoretical load transfer models that currently exist.

The addition of powered components for active assays into paper-based analytical devices opens new opportunities for medical and environmental analysis in resource-limited applications. Current battery designs within such devices have yet to adopt a ubiquitous circuitry material, necessitating investigation into printed circuitry for scalable platforms. In this study, a microfluidic battery was mated with silver-nanoparticle conductive ink to prototype an all-printed sensing platform. A multi-layer, two-cell device was fabricated, generating 200 μA of direct electrical current at 2.5 V sustained for 16 minutes with a power loss of less than 0.1% through the printed circuitry. Printed circuitry traces exhibited resistivity of 75 to 211 10-5 Ω m. Resistance of the printed traces increased upwards of 200% depending on fold angle and directionality. X-ray diffraction confirmed the presence of face-centered cubic silver after sintering printed traces for 30 minutes at 150°C in air. A conductivity threshold was mapped and an ink concentration of 0.636 μL mm-3 was identified as the lower limit for optimal electrical performance.

The functionalization of surfaces has received attention because the process allows the design and tailoring of substrate surfaces with a new or improved function. "Host-guest" thin film complexes are composed of "host" molecules attached the substrate surface, either through physisorption or covalent bonds, with cavities for the inclusion of desired "guest" molecules for the functionalization of the surface. Two methods for fabricating functional "host-guest" thin films were investigated: Langmuir-Blodgett (LB) deposition and self-assembly monolayer (SAM). Langmuir films were created at the air-water interface using octadecanesulfonic acid (C18S) as the amphiphilic "host" molecules separated by hydrophilic guanidinium (G) spacer molecules, which created a cavity allowing the inclusion of desired "guest" molecules. Surface pressure-area isotherms of the (G)C18S, with and without guests, are characterized by the lift-off molecular areas and are use to determine the proper deposition surface pressure. "Host-guest" Langmuir films are deposited onto silicon substrates using the LB deposition technique. The LB films were then subjected to stability testing using different solvents over increasing periods of time. Grazing-angle incidence X-ray diffraction (GIXD), specular X-ray reflectivity (XRR) and transfer ratio measurements were used to characterize the crystallinity, film thickness, overall film stability and film coverage. The GIXD data revealed that the crystallinity of the deposited film varies with the "guest" molecules and can be disrupted by the functional group on the "guest" molecule through hydrogen bonding. After modeling the XRR data using StochFit, it was discovered that the more polar solvent, tetrahydrofuran (THF), removed the film completely while the nonpolar solvent, hexane, compacted the thin film and increased the electron density. With transfer ratios around 0.95 to 1.05, the deposited films were homogenous. The second method used was self-assembly monolayers, which differs from Langmuir films in that they are created by a spontaneous chemical synthesis from immersing a substrate into a solution containing an active surfactant. Octadecyltrichlorosilane (OTS) was used initially as a molecule to study the self-assembled monolayer procedure. To study a "host-guest" self-assembled monolayer system, a compound is being synthesized from 9-bromoanthracene. This compound would already contain the cavity necessary for the inclusion of "guest" molecules. The solution that contained OTS was composed of a 4:1 mixture of anhydrous octadecane: chloroform. Silicon substrates with a deposited oxide layer were hydroxylated for the surfactant binding chemical reaction to occur. The OTS SAMs were exposed to the same stability tests as the LB films. Surface contact angle measurements were taken of the OTS SAMs before and after the stability tests. The contact angle prior to the stability tests was 110° (±2°). The contact angle after immersion in THF was 101° (±2°) while the contact angle resulting from immersion in hexane was 105° (±2°). From the contact angle measurements, the degradation of the OTS SAMs was less extensive than that of the (G)C18S LB films. / Master of Science

Analysis of the molecular speciation of organic compounds in solution is essential for the understanding of ionic complexation. The Raman spectroscopic technique was chosen for this purpose because it allows the identification of compounds in different states and it can give information about the molecular geometry from the analysis of the vibrational spectra. In this research the ionisation steps of relevant pharmaceutical material have been studied by means of potentiometry coupled with Raman spectroscopy; the protonation and deprotonation behaviour of the molecules were studied in different pH regions. The abundance of the different species in the Raman spectra of aqueous salicylic acid, paracetamol, citric acid and salicylaldoxime have been identified, characterised and confirmed by numerical treatment of the observed spectral data using a multiwavelength curve-fitting program. The non-destructive nature of the Raman spectroscopic technique and the success of the application of the multiwavelength curve-fitting program demonstrated in this work have offered a new dimension for the rapid identification and characterisation of pharmaceuticals in solution and have indicated the direction of further research. The work also covers the formation of novel cocrystal systems with pharmaceutically relevant materials. The existence of new cocrystals of salicylic acid-nicotinic acid, DLphenylalanine , 6-hydroxynicotinic acid, and 3,4-dihydroxybenzoic acid with oxalic acid have been identified from stoichiometric mixtures using combined techniques of Raman spectroscopy (dispersive and transmission TRS), X-ray powder diffraction and thermal analysis. Raman spectroscopy has been used to demonstrate a number of important aspects regarding the nature of the molecular interactions in the cocrystal. Cocrystals of II salicylic acid ¿ benzamide, citric acid-paracetamol and citric acid -benzamide have been identified with similar analytical approaches and structurally characterised in detail with single crystal X-ray diffraction. From these studies the high selectivity and direct micro sampling of Raman spectroscopy make it possible to identify spectral contributions from each chemical constituent by a peak wavenumber comparison of single-component spectra (API and guest individually) and the two- component sample material (API/guest), thus allowing a direct assessment of cocrystal formation to be made. Correlation of information from Raman spectra have been made to the X-ray diffraction and thermal analysis results. Transmission Raman Spectroscopy has been applied to the study cocrystals for the first time. Identification of new phases of analysis of the low wavenumber Raman bands is demonstrated to be a key advantage of the TRS technique. / Libyan government and Misurata University

In my time at the Laboratory of Membrane and Protein Dynamics at McMaster University, it has been our goal to investigate the fundamental properties of model membranes and how some common membrane molecules, namely water, ethanol, and cholesterol, interact with the bilayer. Our studies employ highly-oriented, solid-supported membranes in order to extract unambiguous structural information perpendicular to and in the plane of the membranes, with the exception of the hydrated powder samples used in probing the effects on ethanol. Both X-ray and neutron scattering were employed to investigate the structural properties of the membranes and neutron scattering was used to infer the dynamical properties. A variety of neutron scattering techniques were used to determine the properties of hydrated lipid bilayers, as described in the first two publications listed. Instruments including a neutron backscattering spectrometer, reflectometer, and time-of-flight spectrometer were used to observe bilayer structure, lipid/water coupling, and water diffusion. We found that hydrated, solid-supported single-bilayers showed no strong coupling between hydration water and lipid tails and the out-of-plane structure of stacked fluid bilayers as well as the anisotropic and anomalous behaviour of hydration water compared to bulk water. Both X-ray and neutron scattering experiments were done to determine the effect of a 2mol% concentration of ethanol on a hydrated lipid powder. X-ray scattering was used to determine the structural changes due to the addition of ethanol and the location of ethanol within the bilayer. This was accomplished by determining areas of increased electron density in the head group and among the acyl tails. The presence of ethanol also attributed to a decrease in lateral lipid diffusion constant in the gel phase, while no significant change was found in fluid bilayers. In the final study outlined in this thesis, the result of a 32.5% concentration of cholesterol in a hydrated, fluid phospholipid membrane is discussed. Coarse-grained molecular simulations and measurements of the lateral structure of the membrane via neutron spectrometry were able to determine the heterogeneous nature of the liquid-ordered phase and the structure of each of the domains in the membrane. The following thesis will introduce model membranes, their relevant components and the scattering of X-rays and neutrons from such matter. Next, experimental techniques, sample constituents, sample preparations, and instruments used in experiments will be described. Then, each study will be introduced and discussed which will showcase the progress made in the field of model membranes. Lastly, an overview of the studies will lead in to future directions for each model system in terms of suggested experiments and general path. / Thesis / Doctor of Philosophy (PhD)

In the study the influence of different dental technical tools on the surface temperature and phase composition of fixed dental prostheses (FDPs) made of yttria-partially stabilized zirconia polycrystals (3Y-/4Y-/5Y-PSZ) was investigated. FDPs were fabricated by using computer-aided manufacturing (CAM). The FDPs were treated with a contra-angle handpiece equipped with different burs and polishers. The resulting surface temperatures were measured with a thermographic camera, and the resulting phase transformations were investigated by X-ray diffraction and quantified by Rietveld refinement. Processing with burs resulted in no phase transformation, but a preferred orientation shift. Using coarse polisher induced a phase transformation to the rhombohedral phase, while fine polishers produced no relevant phase transformations and no preferred orientation shift. Compared to the monoclinic phase (ca. 9% theoretical volume increase), which is associated with low-temperature degradation (LTD), the rhombohedral phase is much more voluminous (ca. 15% theoretical volume increase) and distorted and, therefore, has a greater degradation potential.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19038号 / 農博第2116号 / 新制||農||1031(附属図書館) / 学位論文||H27||N4920(農学部図書室) / 31989 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 木村 恒久, 教授 西尾 嘉之, 教授 髙野 俊幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

The effect of dental technical tools on the phase composition and roughness of 3/4/5 yttria-stabilized tetragonal zirconia polycrystalline (3y-/4y-/5y-TZP) for application in prosthetic dentistry was investigated. Additionally, the X-ray diffraction methods of Garvie-Nicholson and Rietveld were compared in a dental restoration context. Seven plates from two manufacturers, each fabricated from commercially available zirconia (3/4/5 mol%) for application as dental restorative material, were stressed by different dental technical tools used for grinding and polishing, as well as by chewing simulation and thermocycling. All specimens were examined via laser microscopy (surface roughness) and X-ray diffraction (DIN EN ISO 13356 and the Rietveld method). As a result, the monoclinic phase fraction was halved by grinding for the 3y-TZP and transformed entirely into one of the tetragonal phases by polishing/chewing for all specimens. The tetragonal phase t is preferred for an yttria content of 3 mol% and phase t″ for 5 mol%. Mechanical stress, such as polishing or grinding, does not trigger low-temperature degradation (LTD), but it fosters a phase transformation from monoclinic to tetragonal under certain conditions. This may increase the translucency and deteriorate the mechanical properties to some extent.

Zirconium alloys are widely used in the nuclear industry because of their high strength, good corrosion resistance and low neutron absorption cross-section. However, zirconium has strong affinity for hydrogen, which may lead to hydrogen concentration build-up over time during a corrosion reaction when exposed to water. Hydrogen stays in solution at higher temperature but precipitates as zirconium hydrides at ambient temperatures. The formation of zirconium hydrides is considered to be a major cause of embrittlement, in particular as a key step in the mechanism of delayed hydride cracking. Despite the fact that zirconium hydrides have been studied for several decades, the basic nature and mechanisms of hydride formation, transformation and exact structure are not yet fully understood. In order to find the answer to some of these problems, the precipitation and dissolution of hydrides in commercial grade Zr powder were monitored in real time with high resolution synchrotron and neutron radiations, and the whole pattern crystal structure analysis, using Rietveld and Pawley refinements, were performed. For the first time all commonly reported zirconium hydride phases and complete reversible transformation between two different Zr-hydride phases were recorded with a single setup and their phase transformation type have been analyzed. In addition, the preparation route of controversial γ-zirconium hydride (ZrH), its crystal structure and formation mechanisms are also discussed. / <p>Note: The papers are not included in the fulltext online.</p><p>Paper II and III in thesis as manuscript, paper II with title "The phase transformation between the δ and ε Zr hydrides"</p>