No description available.

No description available.

Este trabalho consistiu em uma investigação sobre a utilização da sílica mesoporosa ordenada tipo SBA-15 como veículo para a incorporação, proteção, transporte e liberação de substâncias biológicas de interesse imunológico e/ou terapêutico. Estudos preliminares incluíram experimentos para estudar o recobrimento da sílica SBA -15 com o polímero Eudragit® e a estabilidade dessa sílica tanto em meios experimentais (água e solução PBS) quanto em meios corporais rnimetizados. Ambos esses estudos demonstraram que as propriedades da SBA-15 e do Eudragit possibilitariam o prosseguimento do trabalho. Os experimentos iniciais de liberação foram feitos principalmente com albumina bovina (BSA), e demonstraram a capacidade da sílica de incorporar, em sua estrutura, as diversas moléculas utilizadas, bem como a influência do Eudragit sobre a dinâmica de liberação, sobretudo em meio ácido. Também foi explorada a incorporação de compostos à SBA-15 sob pressão, tanto in-situ quanto ex-situ. As intensidades relativas dos picos de difração mostraram ser sensíveis à exerção de pressão sobre a amostra, especialmente no que se referiu à incorporação de insulina. Os experimentos in-si tu durante a incorporação e liberação de insulina ajudaram a elucidar a dinâmica desses fenômenos, através da adaptação do modelo teórico, originalmente utilizado em estudos sobre a síntese da SBA-15. Nesse modelo, parâmetros de ajuste foram monitorados durante o experimento e a partir da sua evolução conclusões puderam ser traçadas. A instrumentação necessária para os experimentos in-situ foi desenvolvida, e fica aqui documentada para referências futuras em experimentos envolvendo soluções expostas ao feixe de raios X, especialmente no equipamento Nanostar, onde o arranjo foi originalmente implementado. Os procedimentos de análise, incluindo o modelo teórico, também ficam à disposição para que estudos futuros possam ser executados. A introdução teórica (Cap. 2), complementada pelos apêndices C e B, fica como resumo da teoria e da técnica para os interessados, que podem ainda consultar a literatura para maiores detalhes. / This work consisted of an investigation on the use of SBA-15-type ordered mesoporous sílica as a vehicle for incorporation, protection, transport and release of biological substances for ímmunologic and/or terapeutic processes. Preliminary studies included experiments regarding the coating ofthe SBA-15 sílica with the Eudragit® polymer and the stability of SBA-15 in experimental media (water and PBS solution) and in simulated body fluids. Both studies demonstrated that the properties o f SBA -15 and Eudragit allowed for continuation o f the work. The initial experiments were performed mainly with bovine serum a1bumin (BSA), and showed the silica\'s capacity of incorporating, in its structure, the various molecules, as well as the influence of Eudragit on the release dynamics. Also, the íncorporation of molecules into SBA-15 under pressure, both in-situ and ex-situ, was explored. The relative intensities of the diffraction peaks were found to be susceptible to the pressure exerted on the sample, especially regarding insulin. In-situ experiments made during the incorporation and release o f insulin helped elucidate the dynamics of those phenomena, through the adaptation of the theoretical model, which was or~ginally desinged to study the synthesis process of the sílica. In this model, fit parameters were monitored during the experiment and from their behavior some conclusions were drawn. The necessary instrumentation for the in-situ experiments was developed, and is documented for future referene in experiments involving the exposure of solutions ro X-rays, especially in the Nanostar, where it was originally designed. The analysis procedures, including the theoretical model, are also available for future studies. The theoretical introduction (Chap. 2), together with appendices B and Ç, is left for those interested in the theory and technique, who are also referred to the literature for further details.

O objetivo desse projeto foi o de produzir sílica mesoporosa ordenada (SMO) do tipo SBA-15 com fósforos. A incorporação dos fósforos às paredes da sílica foi realizada através de um único processo de síntese. Os métodos experimentais utilizados para caracterização das amostras foram: RBS (Rutherford Backscattering Spectrometry) para a análise química, SAXS (Small Angle X Ray Scattering), XRD (X Ray Diffraction) e NAI (Nitrogen Adsorption Isotherms) para a análise estrutural destes materiais, além da fotoluminescência. Para a caraterização morfológica complementar das amostras, foi utilizado o SEM (Scanning Electron Microscopy). A incorporação de Eu na matriz de sílica preserva a estrutura de poros ordenada. Os resultados de XRD mostraram a formação de óxidos de európio. A partir dos resultados obtidos observaram-se diferentes efeitos da presença e ausência de sobrenadante durante o período de secagem nas amostras preparadas, como por exemplo, alterações de morfologia. As amostras preparadas com sobrenadante apresentaram menor área superficial e volume de poros. Materiais que mantiveram o sobrenadante apresentaram maior conteúdo de Eu e maior intensidade de luminescência. / The aim of this project was to synthesize ordered mesoporous silica (OMS) with phosphorus. The incorporation of phosphorus to the silica walls was performed by means of a one pot synthesis process. The experimental methods used to characterize the samples were: RBS (Rutherford Backscattering Spectrometry) for chemical analysis, SAXS (Small Angle X Ray Scattering), XRD (X Ray Diffraction) and NAI (Nitrogen Adsorption Isotherms) for structural analysis, besides fluorescence. SEM (Scanning Electron Microscopy) was used for complementary morphological characterization of the samples. The Eu incorporation in the silica matrix preserves the ordered mesoporous structure. The XRD results showed the presence of europium oxides. The presence and absence of the liquid solution during the drying process caused the formation of samples with different properties, as, for example, modification in morphology. Samples prepared in the presence of the liquid solutions showed smaller surface area and pore volume. Materials prepared with the liquid solution during the drying process presented larger Eu content and higher photoluminescence intensity.

This thesis is dedicated to the exploration of fluid phases confined in nanoporous materials using Nuclear Magnetic Resonance (NMR) techniques, with an aim to benefit catalysis research. Included in this report are studies of pure fluids and their mixtures, confined in titania and silica catalyst supports. These investigations are conducted at industrially-relevant, high-temperature (≥ 180 °C) and high-pressure conditions (up to 13 bar), made possible by a pilot-scale chemical reactor unit, designed to operate inside the strong magnetic fields of an NMR spectrometer. NMR spectroscopy, relaxation and pulsed field gradient (PFG) diffusion experiments were performed on each of the systems discussed in this report. Cyclohexane was initially studied inside a porous titania catalyst support at 188 °C and various pressures up to 13 bar. The adsorption and desorption processes of the cyclohexane were observed, revealing a number of previously unobserved phenomena. In addition to an overall, averaged diffusion coefficient, a slow diffusion coefficient was observed within the PFG NMR data attributable to surface diffusive processes occurring within the material. Additionally, T1 relaxation studies were found to provide experimental evidence for the differing configurations of adsorbed layers on the adsorption and desorption branch of the isotherm. Cyclohexane was subsequently studied alongside fluorobenzene in a series of silica catalyst supports of 6 nm, 10 nm and 20 nm pore size. In doing this, it was hoped that the multiple phenomena observed in the titania experiments might be deconvoluted, allowing a greater level of insight. The diffusivities of the fluids were found to differ significantly between the materials, and greater evidence was found of the slow-diffusing surface phase in each of the materials. Additionally, concentrations of cyclohexane and fluorobenzene in the gas and adsorbed layers inside the pore space were calculated via the results of the PFG NMR experiments, providing a map of confined phase behaviour. Competitive adsorption effects were found to become more significant, the smaller the pore size of the material. The results of the cyclohexane and fluorobenzene in silica studies were modelled, using approaches available in the literature, which were found to give varying levels of prediction. The data set acquired in this thesis was found to provide a useful standard, against which current and future models of confined phase behaviour might be verified.

Este trabalho consistiu em uma investigação sobre a utilização da sílica mesoporosa ordenada tipo SBA-15 como veículo para a incorporação, proteção, transporte e liberação de substâncias biológicas de interesse imunológico e/ou terapêutico. Estudos preliminares incluíram experimentos para estudar o recobrimento da sílica SBA -15 com o polímero Eudragit® e a estabilidade dessa sílica tanto em meios experimentais (água e solução PBS) quanto em meios corporais rnimetizados. Ambos esses estudos demonstraram que as propriedades da SBA-15 e do Eudragit possibilitariam o prosseguimento do trabalho. Os experimentos iniciais de liberação foram feitos principalmente com albumina bovina (BSA), e demonstraram a capacidade da sílica de incorporar, em sua estrutura, as diversas moléculas utilizadas, bem como a influência do Eudragit sobre a dinâmica de liberação, sobretudo em meio ácido. Também foi explorada a incorporação de compostos à SBA-15 sob pressão, tanto in-situ quanto ex-situ. As intensidades relativas dos picos de difração mostraram ser sensíveis à exerção de pressão sobre a amostra, especialmente no que se referiu à incorporação de insulina. Os experimentos in-si tu durante a incorporação e liberação de insulina ajudaram a elucidar a dinâmica desses fenômenos, através da adaptação do modelo teórico, originalmente utilizado em estudos sobre a síntese da SBA-15. Nesse modelo, parâmetros de ajuste foram monitorados durante o experimento e a partir da sua evolução conclusões puderam ser traçadas. A instrumentação necessária para os experimentos in-situ foi desenvolvida, e fica aqui documentada para referências futuras em experimentos envolvendo soluções expostas ao feixe de raios X, especialmente no equipamento Nanostar, onde o arranjo foi originalmente implementado. Os procedimentos de análise, incluindo o modelo teórico, também ficam à disposição para que estudos futuros possam ser executados. A introdução teórica (Cap. 2), complementada pelos apêndices C e B, fica como resumo da teoria e da técnica para os interessados, que podem ainda consultar a literatura para maiores detalhes. / This work consisted of an investigation on the use of SBA-15-type ordered mesoporous sílica as a vehicle for incorporation, protection, transport and release of biological substances for ímmunologic and/or terapeutic processes. Preliminary studies included experiments regarding the coating ofthe SBA-15 sílica with the Eudragit® polymer and the stability of SBA-15 in experimental media (water and PBS solution) and in simulated body fluids. Both studies demonstrated that the properties o f SBA -15 and Eudragit allowed for continuation o f the work. The initial experiments were performed mainly with bovine serum a1bumin (BSA), and showed the silica\'s capacity of incorporating, in its structure, the various molecules, as well as the influence of Eudragit on the release dynamics. Also, the íncorporation of molecules into SBA-15 under pressure, both in-situ and ex-situ, was explored. The relative intensities of the diffraction peaks were found to be susceptible to the pressure exerted on the sample, especially regarding insulin. In-situ experiments made during the incorporation and release o f insulin helped elucidate the dynamics of those phenomena, through the adaptation of the theoretical model, which was or~ginally desinged to study the synthesis process of the sílica. In this model, fit parameters were monitored during the experiment and from their behavior some conclusions were drawn. The necessary instrumentation for the in-situ experiments was developed, and is documented for future referene in experiments involving the exposure of solutions ro X-rays, especially in the Nanostar, where it was originally designed. The analysis procedures, including the theoretical model, are also available for future studies. The theoretical introduction (Chap. 2), together with appendices B and Ç, is left for those interested in the theory and technique, who are also referred to the literature for further details.

O objetivo desse projeto foi o de produzir sílica mesoporosa ordenada (SMO) do tipo SBA-15 com fósforos. A incorporação dos fósforos às paredes da sílica foi realizada através de um único processo de síntese. Os métodos experimentais utilizados para caracterização das amostras foram: RBS (Rutherford Backscattering Spectrometry) para a análise química, SAXS (Small Angle X Ray Scattering), XRD (X Ray Diffraction) e NAI (Nitrogen Adsorption Isotherms) para a análise estrutural destes materiais, além da fotoluminescência. Para a caraterização morfológica complementar das amostras, foi utilizado o SEM (Scanning Electron Microscopy). A incorporação de Eu na matriz de sílica preserva a estrutura de poros ordenada. Os resultados de XRD mostraram a formação de óxidos de európio. A partir dos resultados obtidos observaram-se diferentes efeitos da presença e ausência de sobrenadante durante o período de secagem nas amostras preparadas, como por exemplo, alterações de morfologia. As amostras preparadas com sobrenadante apresentaram menor área superficial e volume de poros. Materiais que mantiveram o sobrenadante apresentaram maior conteúdo de Eu e maior intensidade de luminescência. / The aim of this project was to synthesize ordered mesoporous silica (OMS) with phosphorus. The incorporation of phosphorus to the silica walls was performed by means of a one pot synthesis process. The experimental methods used to characterize the samples were: RBS (Rutherford Backscattering Spectrometry) for chemical analysis, SAXS (Small Angle X Ray Scattering), XRD (X Ray Diffraction) and NAI (Nitrogen Adsorption Isotherms) for structural analysis, besides fluorescence. SEM (Scanning Electron Microscopy) was used for complementary morphological characterization of the samples. The Eu incorporation in the silica matrix preserves the ordered mesoporous structure. The XRD results showed the presence of europium oxides. The presence and absence of the liquid solution during the drying process caused the formation of samples with different properties, as, for example, modification in morphology. Samples prepared in the presence of the liquid solutions showed smaller surface area and pore volume. Materials prepared with the liquid solution during the drying process presented larger Eu content and higher photoluminescence intensity.

No description available.

No description available.

Des carbones dérivés de carbures à porosité monodisperse et nanocentrée autour de 0,6 nm ont été préparés par fluoration de carbures via l’arrachement sélectif de l’élément métallique et le maintien de l’empreinte carbonée initiale. Les carbures précurseurs ont été choisis parmi deux des classes de carbures à savoir interstitiels pour le carbure de titane et de niobium et covalents pour le carbure de silicium. La fluoration directe procédant sous flux d’une atmosphère de fluor pur apparait comme étant la seule méthode de fluoration apte à déstabiliser les poudres cristallisées. Appliquée au carbure de titane, des matériaux à teneur variable en carbone et en trifluorure de titane ont été obtenus et caractérisés structuralement par Diffraction des Rayons X quantitative, spectroscopies IR et Raman et leur texture sondée par Microscopie Electronique à Balayage et à Transmission et isothermes d’adsorption à l’azote à 77K. Ils ont aussi été évalués comme matériau d’électrode de supercondensateurs. La fluoration du carbure de silicium pour la stabilisation d’une phase carbonée est plus difficile et seule l’abaissement de la cristallinité du carbure par l’utilisation d’une mise en forme de type couche mince combinée à une méthode de fluoration alternative par décomposition de l’agent fluorant XeF2 ont permis d’obtenir une couche mince de carbone nanostructurée valorisable comme lubrifiant solide et aux propriétés de mouillabilité modulables. / Carbide-derived Carbons (CDC) with monodisperse ultramicroporosity have been prepared by carbide fluorination thanks to selective etching of metallic element. The chosen carbides precursors were titanium and niobium carbides, and silicon carbides from interstitial and covalent carbide family, respectively. Direct fluorination proceeding by a pure flow of 1 atm. of molecular fluorine is the only fluorination way which leads to the transformation of the powdered and highly crystallized carbide into some carbons. Materials with different ratio of carbon and solid titanium trifluoride were successfully obtained by direct fluorination of titanium carbide, characterized by quantitative XRD, IR and Raman spectroscopies and Scanning and Transmission Electronic Microscopies and used in supercapacitors. The direct fluorination of silicon carbide in order to form carbon is more difficult because of the competition between carbon formation and its degradation into gaseous carbon fluorides. To success in our goal, thin film morphology was used as precursor. However, an accurate fluorination way is needed and decomposition of XeF2 fluorinating agent was chosen. Thin films with variable thickness of nanostructured carbon at the surface were obtained and used as solid lubricant with tunable wettability properties.