Aerogels are extremely high surface area, low density materials with applications including thermal and acoustic insulators, radiation detectors and cometary dust particle traps. However, their low density and aggregate structure makes them extremely fragile and practically impossible to machine or handle without breaking. This has led to the development of aerogel composites with enhanced mechanical properties through the addition of polymers or surface modifiers. To date, attempts to strengthen aerogels have come with significant increases in density and processing time. Here I will describe our search for a solution to these problems with our invention using methyl cyanoacrylate chemical vapor deposition (CVD) to strengthen silica, aminated silica and bridged polysilsesquioxane aerogels. This approach led to a strength improvement of the composites within hours and the strongest composite prepared had a 100x strength improvement over the precursor aerogel. We also developed the first approach to control the molecular weight of the polymers that reinforce silica aerogels using surface-initiated atom transfer radical polymerization (SI-ATRP). Although PMMA reinforcement of silica aerogels improved the mechanical properties, further strength improvements were achieved by cross-linking the grafted PMMA. Additionally, we developed the first silica aerogels reinforced with polyaniline nanofibers that were strong and electrically conductive. Reinforcing silica aerogels with polyaniline allowed them to be used as a sensor for the detection of protonating and deprotonating gaseous species. Finally we developed a new approach for the synthesis of silica and bridged polysilsesquioxane spheres using a surfactant free synthesis. This approach allowed for the first in-situ incorporation of base sensitive functionalities during the sol-gel polymerization.

In this work, thermosensitive hydrogels having tunable thermo-mechanical properties were synthesized. Generally the thermal transition of thermosensitive hydrogels is based on either a lower critical solution temperature (LCST) or critical micelle concentration/ temperature (CMC/ CMT). The temperature dependent transition from sol to gel with large volume change may be seen in the former type of thermosensitive hydrogels and is negligible in CMC/ CMT dependent systems. The change in volume leads to exclusion of water molecules, resulting in shrinking and stiffening of system above the transition temperature. The volume change can be undesired when cells are to be incorporated in the system. The gelation in the latter case is mainly driven by micelle formation above the transition temperature and further colloidal packing of micelles around the gelation temperature. As the gelation mainly depends on concentration of polymer, such a system could undergo fast dissolution upon addition of solvent. Here, it was envisioned to realize a thermosensitive gel based on two components, one responsible for a change in mechanical properties by formation of reversible netpoints upon heating without volume change, and second component conferring degradability on demand. As first component, an ABA triblockcopolymer (here: Poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (PEPE) with thermosensitive properties, whose sol-gel transition on the molecular level is based on micellization and colloidal jamming of the formed micelles was chosen, while for the additional macromolecular component crosslinking the formed micelles biopolymers were employed. The synthesis of the hydrogels was performed in two ways, either by physical mixing of compounds showing electrostatic interactions, or by covalent coupling of the components. Biopolymers (here: the polysaccharides hyaluronic acid, chondroitin sulphate, or pectin, as well as the protein gelatin) were employed as additional macromolecular crosslinker to simultaneously incorporate an enzyme responsiveness into the systems. In order to have strong ionic/electrostatic interactions between PEPE and polysaccharides, PEPE was aminated to yield predominantly mono- or di-substituted PEPEs. The systems based on aminated PEPE physically mixed with HA showed an enhancement in the mechanical properties such as, elastic modulus (G′) and viscous modulus (G′′) and a decrease of the gelation temperature (Tgel) compared to the PEPE at same concentration. Furthermore, by varying the amount of aminated PEPE in the composition, the Tgel of the system could be tailored to 27-36 °C. The physical mixtures of HA with di-amino PEPE (HA·di-PEPE) showed higher elastic moduli G′ and stability towards dissolution compared to the physical mixtures of HA with mono-amino PEPE (HA·mono-PEPE). This indicates a strong influence of electrostatic interaction between –COOH groups of HA and –NH2 groups of PEPE. The physical properties of HA with di-amino PEPE (HA·di-PEPE) compare beneficially with the physical properties of the human vitreous body, the systems are highly transparent, and have a comparable refractive index and viscosity. Therefore,this material was tested for a potential biological application and was shown to be non-cytotoxic in eluate and direct contact tests. The materials will in the future be investigated in further studies as vitreous body substitutes. In addition, enzymatic degradation of these hydrogels was performed using hyaluronidase to specifically degrade the HA. During the degradation of these hydrogels, increase in the Tgel was observed along with decrease in the mechanical properties. The aminated PEPE were further utilised in the covalent coupling to Pectin and chondroitin sulphate by using EDC as a coupling agent. Here, it was possible to adjust the Tgel (28-33 °C) by varying the grafting density of PEPE to the biopolymer. The grafting of PEPE to Pectin enhanced the thermal stability of the hydrogel. The Pec-g-PEPE hydrogels were degradable by enzymes with slight increase in Tgel and decrease in G′ during the degradation time. The covalent coupling of aminated PEPE to HA was performed by DMTMM as a coupling agent. This method of coupling was observed to be more efficient compared to EDC mediated coupling. Moreover, the purification of the final product was performed by ultrafiltration technique, which efficiently removed the unreacted PEPE from the final product, which was not sufficiently achieved by dialysis. Interestingly, the final products of these reaction were in a gel state and showed enhancement in the mechanical properties at very low concentrations (2.5 wt%) near body temperature. In these hydrogels the resulting increase in mechanical properties was due to the combined effect of micelle packing (physical interactions) by PEPE and covalent netpoints between PEPE and HA. PEPE alone or the physical mixtures of the same components were not able to show thermosensitive behavior at concentrations below 16 wt%. These thermosensitive hydrogels also showed on demand solubilisation by enzymatic degradation. The concept of thermosensitivity was introduced to 3D architectured porous hydrogels, by covalently grafting the PEPE to gelatin and crosslinking with LDI as a crosslinker. Here, the grafted PEPE resulted in a decrease in the helix formation in gelatin chains and after fixing the gelatin chains by crosslinking, the system showed an enhancement in the mechanical properties upon heating (34-42 °C) which was reversible upon cooling. A possible explanation of the reversible changes in mechanical properties is the strong physical interactions between micelles formed by PEPE being covalently linked to gelatin. Above the transition temperature, the local properties were evaluated by AFM indentation of pore walls in which an increase in elastic modulus (E) at higher temperature (37 °C) was observed. The water uptake of these thermosensitive architectured porous hydrogels was also influenced by PEPE and temperature (25 °C and 37 °C), showing lower water up take at higher temperature and vice versa. In addition, due to the lower water uptake at high temperature, the rate of hydrolytic degradation of these systems was found to be decreased when compared to pure gelatin architectured porous hydrogels. Such temperature sensitive architectured porous hydrogels could be important for e.g. stem cell culturing, cell differentiation and guided cell migration, etc. Altogether, it was possible to demonstrate that the crosslinking of micelles by a macromolecular crosslinker increased the shear moduli, viscosity, and stability towards dissolution of CMC-based gels. This effect could be likewise be realized by covalent or non-covalent mechanisms such as, micelle interactions, physical interactions of gelatin chains and physical interactions between gelatin chains and micelles. Moreover, the covalent grafting of PEPE will create additional net-points which also influence the mechanical properties of thermosensitive architectured porous hydrogels. Overall, the physical and chemical interactions and reversible physical interactions in such thermosensitive architectured porous hydrogels gave a control over the mechanical properties of such complex system. The hydrogels showing change of mechanical properties without a sol-gel transition or volume change are especially interesting for further study with cell proliferation and differentiation. / In der vorliegenden Arbeit wurden thermosensitive Hydrogele mit einstellbaren thermo-mechanischen Eigenschaften synthetisiert. Im Allgemeinen basiert der thermische Übergang thermosensitiver Gele auf einer niedrigsten kritischen Löslichkeitstemperatur (LCST) oder kritischer Mizellkonzentration bzw. –temperatur(CMC/ CMT). Der temperaturabhängige Übergang von Sol zu Gel mit großer Volumenänderung wurde im ersten Fall bei thermosensitiven Hydrogelen beobachtet und ist vernachlässigbar für CMC/ CMT abhängige Systeme. Die Änderung des Volumens führt zum Ausschluss von Wassermolekülen, was zum Schrumpfen und Versteifen des Systems oberhalb der Übergangstemperatur führt. Die Volumenänderung kann unerwünscht sein, wenn Zellen in das Gel eingeschlossen werden sollen. Die Gelierung im zweiten Fall beruht hauptsächlich auf der Mizellbildung oberhalb der Übergangstemperatur und weiterem kolloidalem Packen von Mizellen im Bereich der Gelierungstemperatur. Weil die Gelierung hauptsächlich von der Polymerkonzentration abhängt, kann sich das Gel bei Zugabe von Lösungsmittel leicht wieder lösen. Hier sollten thermosensitive Gele entwickelt werden, die auf zwei Komponenten beruhen. Eine Komponente sollte aus einem ABA-Triblockcopolymer mit thermosensitiven Eigenschaften bestehen, dem Poly(ethylen glycol)-b-Poly(propylenglycol)-b-Poly(ethylen glycol) (PEPE), dessen Sol-Gel-Übergang auf Mizellierung und kolloidalem Jamming der gebildeten Mizellen basiert, und einer weiteren makromolekularen Komponente, einem Biopolymer, dass die Mizellen vernetzt. Auf diese Weise sollten thermosensitive Gele realisiert werden, die keine oder nur eine kleine Volumenänderung während der Änderung der mechanischen Eigenschaften zeigen, die stabiler gegenüber Verdünnung sein sollten als klassische Hydrogele mit einem CMC-basierten Übergang und die jedoch gezielt abgebaut werden können. Die Hydrogele wurden auf zwei Arten vernetzt, entweder durch physikalisches Vermischen, bei dem die Vernetzung durch elektrostatische Wechselwirkungen erfolgte, oder durch kovalente Kopplung der beiden Komponenten. Als makromolekulare Komponente zur Vernetzung der Mizellen wurden Biopolymere (hier: die Polysaccharide Hyaluronsäure (HA), Chondroitinsulfat oder Pektin oder das Protein Gelatin) verwendet, um die Hydrogele enzymatisch abbaubar zu gestalten. Um eine starke ionische/elektrostatische Wechselwirkung zwischen dem PEPE und den Polysachariden zu erzielen, wurde PEPE aminiert, um hauptsächlich monoaminiertes bzw. diaminiertes PEPE einsetzen zu können. Die Gele, die auf der physikalischen Mischung von aminierten PEPE mit HA bestehen, zeigten im Vergleich zu PEPE bei gleicher Konzentration eine Zunahme der mechanischen Eigenschaften, wie beispielsweise dem elastischem Modulus (G′) und dem Viskositätsmodulus (G′′) bei gleichzeitiger Abnahme der Gelierungstemperatur (Tgel). Durch Variation des Gehalts an aminierten PEPE-, konnte die Tgel in einem Bereich von 27-36 °C eingestellt werden. Interessanterweise zeigten die physikalischen Mischungen mit diaminierten PEPE (HA·di-PEPE) höhere mechanische Eigenschaften (elastischer Modulus G′) und eine höhere Stabilität gegenüber Verdünnungseffekten als Mischungen mit monoaminiertem PEPE (HA·mono-PEPE). Dies zeigt den starken Einfluss der elektrostatischen Wechselwirkungen zwischen der Carboxylgruppe der HA und der Amingruppe von PEPE. Die physikalischen Eigenschaften HA·di-PEPE sind vergleichbar mit den physikalischen Eigenschaften des Glaskörpers im Auge hinsichtlich Transparenz, Brechungsindex und Viskosität. Deswegen wurde das Material hinsichtlich seiner biologischen Anwendung getestet und zeigte sich sowohl im Überstand als auch im direkten Kontakt als nichtzytotoxisch. Zukünftig wird dieses Material in weiteren Untersuchungen bezüglich seiner Eignung als Glaskörperersatz geprüft werden. Zusätzlich konnte der enzymatische Abbau der Hydrogele mit Hyaluronidase gezeigt werden, die spezifisch HA abbaut. Beim Abbau der Hydrogele stieg Tgel bei gleichzeitiger Abnahme der mechanischen Eigenschaften. Aminiertes PEPE wurde zusätzlich zur kovalenten Bindung unter Verwendung von EDC als Aktivator an Pektin und Chondroitinsulfat eingesetzt. Tgel konnte auf 28 – 33 °C eingestellt werden durch Variation der Pfropfungsdichte am Biopolymer bei gleichzeitiger Zunahme der thermischen Stabilität. Die Pec-g-PEPE Hydrogele waren enzymatisch abbaubar, was zu einer leichten Erhöhung von Tgel und zu einer Abnahme von G′ führte. Die kovalente Bindung der aminierten PEPE an HA erfolgte unter Verwendung von DMTMM als Aktivator, der sich in diesem Fall als effektiver als EDC herausstellte. Die Reinigung mittels Ultrafiltration führte zu einer deutlich besseren Aufreinigung des Produkts als mittels Dialyse. Die gegrafteten Systeme waren in Nähe der Körpertemperatur bereits im Gelstadium und zeigten eine Erhöhung der mechanischen Eigenschaften bereits bei sehr geringen Konzentrationen von 2.5Gew.%. Die höheren mechanischen Eigenschaften dieser Hydrogele erklären sich durch die Kombination der Mizellbildung (physikalische Wechselwirkung) des PEPE und der Bildung kovalenter Netzpunkte zwischen PEPE und HA. PEPE bzw. entsprechende physikalische Mischungen derselben Komponenten zeigten kein thermosensitives Verhalten bei einer Konzentration unterhalb von 16 Gew%. Diese thermosensitiven Hydrogele zeigten auch eine Löslichkeit auf Abruf durch enzymatischen Abbau. Das Konzept der Thermosensitivität wurde in 3D strukturierte, poröse Hydrogele (TArcGel)eingeführt, bei dem PEPE kovalent an Gelatin gebunden wurde und mit LDI vernetzt wurde. Das gepfropfte PEPE führte zu einer Erniedrigung der Helixbildung der Gelatinketten. Nach Fixierung der Gelatinketten durch Vernetzung zeigte das System eine Erhöhung der mechanischen Eigenschaften bei Erwärmung (34-42 °C). Dieses Phänomen war reversibel beim Abkühlen. Eine mögliche Erklärung der reversiblen Änderungen bezüglich der mechanischen Eigenschaften sind die starken physikalischen Wechselwirkungen zwischen den Mizellen des PEPE, die kovalent an Gelatin gebunden wurden. Ferner wurde durch AFM Untersuchungen festgestellt, dass bei Temperaturerhöhung (37 °C) die örtlichen elastischen Moduli (E) der Zellwände zugenommen haben. Zusätzlich wurde die Wasseraufnahme der TArcGele durch PEPE und die Temperatur (25 °C und 37 °C) beeinflusst und zeigte eine niedrigere Wasseraufnahme bei höherer Temperatur und umgekehrt. Durch die niedrigere Wasseraufnahme bei hohen Temperaturen erniedrigte sich die Geschwindigkeit des hydrolytischen Abbaus im Vergleich zu dem strukturierten Hydrogel aus reiner Gelatin. Diese temperatursensitiven ArcGele könnten bedeutsam sein für Anwendungen im Bereich Stammzellkultivierung, Zelldifferenzierung und gerichteter Zellmigration. Zusammenfassend konnte bei den thermosensitiven Hydrogelen gezeigt werden, dass die Vernetzung von Mizellen mit einem makromolekularen Vernetzer die Schermoduli, Viskosität und Löslichkeitsstabilität im Vergleich zu reinen ABATriblockcopolymeren mit CMC-Übergang erhöht. Dieser Effekt konnte durch kovalente und nichtkovalente Mechanismen, wie beispielsweise Mizell- Wechselwirkungen, physikalische Interaktionen von Gelatinketten und physikalische Interaktionen von Gelatinketten und Mizellen, realisiert werden. Das Pfropfen von PEPE führte zu zusätzlichen Netzpunkten, die die mechanischen Eigenschaften der thermosensitiven architekturisierten, porösen Hydrogele beeinflussten. Insgesamt ermöglichten die physikalischen und chemischen Bindungen und die reversiblen physikalischen Wechselwirkungen in den strukturierten, porösen Hydrogelen eine Kontrolle der mechanischen Eigenschaften in diesem sehr komplexen System. Die Hydrogele, die eine Veränderung ihrer mechanischen Eigenschaften ohne Volumenänderung oder Sol-Gel-Übergang zeigen sind besonders interessant für Untersuchungen bezüglich Zellproliferation und –differenzierung.

Darbo tikslas yra pagaminti La2O3 sluoksnius, atkaitinant prie aukštų temperatūrų nenaudojant vakuumo ir ištirti gautų sluoksnių Rentgeno fotoelektronų spektrus. Darbe aprašyti Rentgeno fotoelektronų spektroskopijos (RFS) (XPS - X-ray photoelectron spectroscopy) metodo, naudojamo įvairių medžiagų paviršių cheminei sudėčiai nustatyti, pagrindai. Pirmajame skyriuje aprašytas Rentgeno fotoelektroninės spektroskopijos metodas, pagrindinė RFS aparatūra bei teorinė dalis. Antrajame skyriuje aprašyti: La2O3 oksidiniai junginiai ir jų tyrimų metodika, plonų nanostruktūrizuotų medžiagų sluoksnių nusodinimo iš dujų fazės (plazmos) metodas- magnetroninis dulkinimas (magnetron sputtering), aparatūra ir zolis – gelis metodas. Trečiasis skyrius yra skirtas Rentgeno fotoelektroninių spektrų matavimų, naudojant spektrometrą XSAM 800 (Kratos Analytical, Didžioji Britanija) ypatumams ir bandinių gamybos metodikai aptarti. Pateiktas išsamus La2O3 sintezės zolių-gelių metodu technologijos aprašymas. Ketvirtajame skyriuje pateikiami eksperimentiniai rezultatai gauti, matuojant La2O3 Rentgeno fotoelektronų spektrus. Darbo pabaigoje yra pateikiamos išvados, kurios galėtų būti naudingos, tobulinant La2O3 bandinių gamybos technologiją. Gautas rezultatas: nustatyta, kad zolių – gelių technologija leidžia paprastais metodais, nenaudojant sudėtingos aparatūros,bei vakuuminės įrangos susintetinti La2O3. / The aim of presented work was to synthesis by using sol-gel technology and investigate the X- ray photoelectron spectra (XPS) of La2O3 thin films in the annealed high temperature and without using vacuum installation. In the present work we described the essentials of the method of X-ray photoelectron spectroscopy, used to determine chemical composition of various materials. In the first part describes the X- ray photo-electronic spectroscopy method, basic XPS equipment and theoretical part. The second part are described: La2O3 oxide compounds and the methods of their production from the gas phase – magnetron sputtering and sol – gel method. In the third part we discussed the peculiarities and methodology of spectrometer XSAM 800 (Kratos Analytical, Great Britain) samples production while measuring X-ray photoelectron spectra. The thorough description of the technology by synthesis of La2O3 sol-gel method was provided. The fourth part presents the experimental results obtained by measuring the La2O3X-ray photoelectron spectra. In the end of the work conclusions are produced that could be useful in improving production technology of La2O3 samples. Obtained results: we identified that sol-gel technology allows synthesizing La2O3 by simple methods, without using sophisticated equipment and vacuum installation.

The interaction between metal nanoparticles and small molecules has been investigated by FTIR and UV-visible absorption spectroscopy. Electrospray deposition into an argon matrix was chosen as the initial method. An electrospray metal source was tested in development stage. Both the formation of a stable corona discharge as well as a stable Taylor cone were successfully completed. Problems arose when the entire system was tested. It was determined that the vacuum was insufficient for the length of the flight path. Focus then shifted to nanoparticles in more conventional environments. Sol-gel encapsulated nanoparticles were generated, in the form of both monoliths as well as thin film coatings on silicon wafers. The gels were exposed to 1atm of carbon monoxide in a gas cell. The method encountered problems due to spectral interference from the matrix. The next attempt consisted of solution stabilized nanoparticles. The solution was exposed to various amounts of both ammonium sulphate and diethylamine. There was again the problem of solvent interference, even when attempting to observe the system using Raman spectroscopy. Finally, surface stabilized nanoparticles were generated, using 3-mercaptopropyltrimethoxysilane to adhere the particles to glass slides. While the coating was successfully applied to the glass slides, as confirmed with Raman spectroscopy, it was not possible to get the nanoparticles to adhere. Future outlook for this project is briefly reviewed. / Thesis (Master, Chemistry) -- Queen's University, 2009-06-26 10:30:58.295

The complex dose distributions delivered by modern, conformal radiation therapy techniques present a considerable challenge in dose verification. Traditional measurement tools are difficult and laborious to use, since complete verification requires that the doses be determined in three dimensions (3D). The difficulty is further complicated by a required target accuracy of ± 5% for the dose delivery. Gel dosimetry is an attractive option for realizing a tissue-equivalent, 3D dose verification tool with high resolution readout capabilities. However, much important work remains to be completed prior to its acceptance in the clinic. The careful development of easily accessible, fast optical readout tools such as cone beam optical computed tomography (CT) in combination with stable and reliable low-toxicity gel dosimeters is one key step in this process. In this thesis, the performance capabilities and limitations of the two main classes of cone beam optical CT-based absorbing and scattering gel dosimetry are characterized, and their measurement improved through careful matching of dosimeter and scanner performance. These systems are then applied to the evaluation of clinically relevant complex dose distributions. Three-dimensional quality assurance assessments of complex treatment plan dose distributions are shown to be feasible using an optically absorbing Fricke-xylenol-orange-gelatin-based gel dosimeter. Better than 95% voxel agreement is achieved between the plan and the delivery, using 3% dose difference and 3 mm spatial distance-to-agreement gamma function comparison criteria. Small field dose delivery evaluations are demonstrated to be viable using an optically scattering N-isopropylacrylamide (NIPAM)-based polymer gel, with the same comparison criteria. Full treatment process quality assurance is also possible using a NIPAM dosimeter in-phantom, but is limited in its accuracy due to the inherent difficulty of managing the effects of stray light pertubation in the optical attenuation-to-dose calibration. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2010-09-02 15:01:48.501

Metaproteomics, as a proteomic approach to analyse environmental samples, is a new and expanding field of research. The field promises new ways of determining the status of the organisms present in a sample, and could provide additional information compared to metagenomics. Being a novel field of research, robust methods and protocols have not yet been established. In this thesis, we examine several methods for a reliable extraction of protein from soil and periphyton samples. The extraction should preferably be fast, compatible with downstream analysis by mass spectrometry and extract proteins in proportion to their presence in the original sample. A variety of methods and buffers were used to extract proteins from soil and periphyton samples. Concentration determinations showed that all of these methods extracted enough protein for further analysis. For purification and digestion of the samples, several methods were used. The purified samples were analysed on three different mass spectrometers, with the Orbitrap Velos Pro delivering the best results. The results were matched against four genomic and metagenomic databases for identification of proteins, of which the UniProt/SwissProt database gave the best result. A maximum of 52 proteins were identified from periphyton samples when searching against UniProt/SwissProt with strict settings, of which the majority were highly conserved proteins. The main limitation for this type of work is currently the lack of proper metagenomic databases.

Zolis-gelis procesas, kuris turi potencialiai didelę technologinę vertę, leidžia sukurti medžiagas, kurių unikalios struktūros ir savybės yra retai gaunamos naudojant kitus metodus. Šio darbo užduotis- pagaminti Vanadžio-Titano-hidrochinono oksidinę bronzą panaudojant zolis-gelis technologiją bei ištirti vanadžio ir titano jonų valentingumą juose naudojant Rentgeno fotoelektronų spektroskopijos metodą. Darbe aprašoma Zolio-Gelio technologijos pagrindai, Rentgeno fotoelektronų spektroskopija ir jos spinduliuotės prietaisai, bei matavimo metodika. Aprašyti eksperimentiniai bronzos ir vanadžio – titano- hidrochinono kserogelio Rentgeno Fotoelektronų spektrai. Darbe pateikti ir lyginami grafikai buvo braižomi paisnaudojus įvairiomis programomis (SDP, XPS ir Origin). Apibendrinant šio darbo rezultatus, galima teigti, jog Vanadžio- Titano- hidrohinono kserogelyje vanadis yra V5+, V4+ ir V3+ būsenose, o deguonies jonai surišti su vanadžiu, hidroksilinėmis grupėmis ir molekuliniu vandeniu. Vanadžio- Titano- hidrochinono kserogelio kaitinimas aplinkos atmosferoje iki 580K leidžia visiškai pašalinti iš kserogelio chemiškai surišta vandenį, tai yra pereiti nuo kserogelio prie bronzos. / Sol-gel process, which has a potentially high technological value, allows you to create materials with unique structure and properties are reraly generated using other methods. This work made the task – Vanadium-Titanium-hydroquinone oxidic bronze using the sol-gel technology and study of vanadium and titanium ion valence them using X- ray photoelectron spectroscopy. The paper describes the sol-gel technology basics, X-ray photoelectron spectroscopy radiation devices, and measurement techniques. Describe the experimental and vanadium - titanium - hydroquinone xerogels and bronze X-ray photoelectron spectra. The paper presents and compares graphs were drawn from this various programs (SDP, XPS and Original). Summing up the results, one can argue that the vanadium-titanium in xerogel is V5+, V4+ and V3+ states and the oxygen ions are bound to vanadium hydroxyl groups and molecular water. Vanadium- titanium-hydroquinone xerogels heating in the atmosphere to 580K allows to completely remove from the xerogels chemically bound water which is the transition from xerogels to bronze. Vanadium and titanium ions in the bronze are in stable V5+ and Ti4+ states respectively.

Excess water production is a major economic and environmental problem for the oil and gas industry. The cost of processing excess water runs into billions of dollars. Polymer gel technology has been successfully used in controlling water influx without damaging hydrocarbon production in conventional naturally fractured or hydraulically fractured reservoirs. However, there has been no systematic investigation on effectiveness and placement conditions of polymer gels for shutting off water flow from fractures with narrow apertures in shale and tight gas reservoirs. The existing polymer gels, like those based on Chromium(III) Acetate, as a crosslinker will exert very high extrusion pressure to effectively penetrate the narrow aperture fractures present in shale and tight gas reservoirs. This gives rise to a need for a new polymer gel system that can be used for selectively shutting off water flow from narrow aperture fractures in shale and tight gas reservoirs. The new gel system will have a longer gelation time than the existing polymer gels; this ensures minimum crosslinking of the gel by the time it reaches bottom hole. The gelant solution will be pumped at low pressure so that, it penetrates only pre-existing fractures in the formation with ease. This study for the first time focuses on developing an environmentally benign polymer gel system based on high molecular weight HPAM, as a base polymer and a commercial grade PEI as an organic crosslinker. Gel samples of different concentration ratios of the polymer and crosslinker were prepared and classified under Sydansk code of gel strength to find optimum concentration ratios that gave good gels. The gel system was characterized using Brookfield DV-III Ultra Rheometer and Fann-35 Viscometer.

Titanium dioxide is a well-studied and popular photocatalyst, but a number of factors still prevent its widespread use in a number of commercial applications. In this thesis we explored the synthesis of titanium dioxide nanoparticles via the sol-gel method, with the goal of creating a viable catalyst for the visible-light degradation of wastewater dyes. A number of different synthetic pathways were explored and developed, and the products categorised with respect to nanoparticle size, shape and crystallinity as well as electronic and photocatalytic properties.

This dissertation addresses three research areas in the sol-gel synthesis of functionalmaterials. The first is the kinetics of hydrolysis and condensation of variousorganoalkoxysilanes. Two mathematical models are developed for the sol-gel reaction inbasic conditions with and without nearest-neighbor effects. Effects on reactivity aremeasured with systematic changes in the organic group structure. Replacing onemethoxy group on the precursor with a methyl group decelerates hydrolysis under basicconditions, but accelerates condensation under acidic conditions. Replacing two methylfunctionalprecursors with one ethylene-bridged precursor accelerates hydrolysis in base,but decelerates condensation in acid. Replacing an ethylene bridge with a hexylenebridge always decelerates the sol-gel reactions. Adding an amine into the hexylenebridge always accelerates the sol-gel reactions. These trends show inductive effectsplaying a role only under basic conditions, while steric effects play a role at all pHvalues. The second topic of this thesis is the synthesis of organic-inorganic materialswith bridging or non-bridging organics. The structure of the organic-inorganic hybrids ispartially correlated with the kinetics of the precursors, but the trends indicate anadditional structural role of siloxane cyclization. The third topic of this thesis is thesynthesis of surfactant-templated nanoporous particles. The key to preparing orderedhybrid materials is found to be encouraging aggregation with a surfactant whilediscouraging random condensation of silanes independent of the surfactants. Ahomologous series of cationic pyridinium chloride fluorinated surfactants with varyingchain length are used as pore templates. Typical pore structures such as hexagonal closepackedcylinders are synthesized, as well as new pore structures including random meshphase pores and vesicular silica particles with bilayer or multilayer shells.Fluorosurfactants enable the formation of unusually small pores (1.6 nm) and poresformed from discs or bilayers. In the presence of ethanol, spherical particles with radiallyoriented pores are shown by TEM to form by precipitation of disordered silica-surfactantparticles followed by assembly into organized structures. High-capacity hollow particleswith ordered mesoporous shells are prepared by dual latex / surfactant templating.Finally, we load amine-functionalized mesoporous silica with highly dispersedsuperparamagnetic iron oxide nanoparticles.