Non-destructive investigation methods where applied to study evaporation dynamics and other dynamic processes of volatile and non-volatile fluids from different porous membranes. While evaporation dynamics from porous alumina didn't show any irregularities, it was shown that evaporation of ethanol from porous glasses can be divided into two different phases - linear endothermal evaporation and adiabatic burst evaporation.

Sol-gel porous glasses have been doped with indicator molecules for colorimetric measurements of pH and metal ions in solution. pH measurements were made in real time (20 seconds) to a wide pH range 3-8 by using bromophenol blue doped in sol-gel thin films. New methods of sol-gel coating on the inside of test tubes and tubing have been introduced for simple, non invasive, on the spot chemical sensing. pH indicator doped films were also successfully autoclaved for biological applications without affecting their chemical and physical properties. The pore structure of thin films has been controlled for minimising the effect of ageing on response time by introducing dimethyl formamide (DMF). The effect of light, temperature and salt on thin films have been studied. The results show that they are relatively stable between 20-31' C and less affected « 0.03 absorbance unit decrease in 3 weeks) by light. However their response to pH is changed by adding salt in solution with concentration higher than O.OlM. Fourier transform infra red (FTIR) study of films has been conducted to elucidate the effect of ageing, DMF and autoclaving on their chemical structures. It was found that ageing continues after four weeks of fabrication and addition of DMF helps to reduce ageing and increase porosity. The long term stability of these pH indicator doped films in various solvents has been established. Thin films on microscope slides were deposited by using a newly designed spin coater and have been demonstrated as reusable pH slides. Sol-gel films were also doped by different metal reagents. Eriochrome cyanine doped thin films were found to be sensitive to copper ions in solution. Copper (Cu++) was measured to a low concentration of 0.6 ppm. The effect of light and temperature on Eriochrome copper complex was studied. Interferences of other metal ions were examined. A fibre-optic pH sensor has been demon.strated by coating an optical fibre with a sol-gel film (0.8 J.1m thick) doped with bromophenol blue. The sensor has shown fast response (5 seconds) to pH changes from pH 3 to 8 and no leaching or cracking during repeated use. It is simple to fabricate and easy to use as an interchangeable pH fibre probe. It has potential application in biological processes as an integral part of an online monitoring system.

For elucidating catalytic processes and enhancing process efficiency, the characterisation of porous catalysts is crucial. While the chemical characterisation of the catalyst surface, e.g. by infrared and X-ray photoelectron spectroscopy, is standard practice, the energetic characterisation of surface sites is often neglected, although all heterogeneously catalyzed reactions take place at the surface. Inverse gas chromatography is a gas phase method to investigate a large number of physico-chemical, morphological and energetical surface properties of particles, granulates or fibers. In this dissertation, silica materials with well-defined surface properties and a large specific surface area (porous glass beads, pyrogenic silica) were investigated. For potential catalytic and sensoric applications, the silica material was additionally grafted with organofunctional silanes. The overall aim of this Thesis was to apply IGC-theories to different silicas before and after surface modification, to examine the potential of this characterisation method. The validity of the results was set against its limitations, to verify the IGC as sensitive method even for small changes of physico-chemical surface properties. It was observed that the physicochemical properties of the surface are predominatly determined by silanol and siloxane groups. In particular the LEWIS-acid silanol groups strongly interact with LEWIS-basic polar probe molecules. This results in high values for free surface energy with a dominant polar component and an overall LEWIS-acidity of the silica. Measurements indicated specific surface areas respectively to the applied probe molecule. In particular 2-propanol showed strong interactions, a very high surface area, but also a heterogenous adsorption behaviour. According to PAPIRERs Patchwork model of condensation approximation, two different states of adsorption were found. With DFT-simulation these were identified as low energetic hydrogen bonds between 2-propanol and siloxan and as high energetic hydrogen bonds between 2-propanol and silanol groups. Nevertheless, all of the IGC findings point to a reduction of the acidity of silica and an increase in hydrophobicity by surface modification due to the loss of silanol groups with the silane grafting. Finally, the IGC can be presented as a many-faceted useful tool for surface characterisation. Its variability and sensitivity expands most other classical methods. Complex surface properties like free surface energies, acid-base functionality, kinetic parameters, specific surface area and surface heterogenity can be determined from single chromatographic peaks with the respective theories. Throughout the investigation, a new non-linear parameter estimation approach was introduced in contrast to the common linear computation models. Therefore, an increasing number of involved probe molecules and also the use of bipolar probes yields in statistical more reliable results.

A novel fiber optic structure, termed stochastic ordered hole fibers, has been developed that contains an ordered array of six hollow tubes surrounding a hollow core, combined with a nanoporous glass creating a unique fully three dimensional pore/fiber configuration. The objective of this study is to increase the functionality of these stochastic ordered hole fibers, as well as porous clad fibers, by integrating electronic device components such as conductors, and semiconductors, and optically active materials on and in the optical fiber pore structures. Conductive copper pathways were created on/in the solid core fibers using an electroless deposition technique. A chemical vapor deposition system was built in order to attempt the deposition of silicon in on the porous clad fibers. Additionally, conductive poly(3,4-ethylenedioxythiophene)- poly(styrene sulfonate) (PEDOT:PSS) and photoactive polymer blend poly(3- hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-)6,6)C61 (P3HT: PCBM) were deposited on the fibers using dip coating techniques. Quantum dots of Cadmium Selenide (CdSe) with particle sizes of ranging from 2- 10 nm were deposited in the stochastic ordered hole fibers. SEM and EDS analysis confirm that copper, polymer materials, and quantum dots were deposited in the pore structure and on the surface of the fibers. Finally, resistance measurements indicate that the electrolessly deposited copper coatings have sufficient conductivity to be used as metallic contacts or resistive heating elements. / Master of Science

Despite recent advances in stem cell biology, immunotherapy and transplantation, substantial barriers still exist in the large-scale specific separation of a discrete population of human therapeutic cells from a cell suspension. The ideal purification technique should combine high cell purity, yield and function, with fast processing and affordability. Currently, fluorescence-activated cell sorting with flow cytometry (FACS) and magnetic activated cell sorting (MACS®) are the most used methods for cell separation and purification and have been employed extensively in molecular biology, diagnostic and cell sorting applications, because they are considered to be gentle, fast and scalable. However, these methods have several key disadvantages; they are invariably expensive, yield low log cell reduction (LCR) rates, and suffer from drawbacks when applied to niche cell populations, such as those requiring multiple tandem separation steps and/or involving combined positive and negative cell selection steps. To address this challenge, a new cell affinity selection system was developed. The selectivity is based on the reversible monomeric avidin biotin interaction and it is primary designed for positive selection. The initial studies were performed on flat, nonporous, glass coverslips and the technology was then successfully transferred on high grade smooth non-porous glass beads (with a diameter of 79.12 to 118.59 μm). The multi-step layer-by-layer deposition procedure culminating in dextran-coated supports bearing monomeric avidin was rigorously characterized and subsequently employed in packed bed chromatography experiments with human erythrocytes isolated from cord blood and B lymphocytes from cell lines. The developed affinity selection platform was highly selective, efficient and, most importantly, resulted in high yields, cell purity and viability comparable with MACS® technology. Additionally scale up is possible and could be easily transferred to another chromatographic matrix with the appropriate structure.

Apresentamos um estudo de solidificaçaõ e lixiviacão de matrizes de vidros porosos de alto teor de sílica armazenando 20% em peso de solução aquosa simuladora de rejeitos nucleares de alto nível de radioatividade do tipo Savanah River Labratory. A matriz porosa foi preparada após o tratamento térmico de um vidro de 65% SiO2-27%B2O3-8%Na2O, que sofreu separação de fase à 560°C por 20 horas e lixiviado em HCl - 3N à 90°C. O tamanho dos poros (tipicamente de 100 à 250Å de diâmetro) , foi determinado utilizando o método BET. Após sinterização à 1300°C em ar, as amostras foram caracterizadas física e quimicamente através de testes de lixiviação padronizados MCC1, Soxhlet (MCC5) e Estagnante durante cerca de 28 dias. Determinamos a perda de peso total, o pH, as taxas de lixiviação diferencial e as concentrações acumuladas para os seguintes elementos: Si, Na, B, Ca, Mn, Al, Fe e Ni com técnicas de ICP e espectroscopia de chama para o caso do Na. Os resultados são comparados com os obtidos com vidros borosilicatos de referência, fabricados por fusão convencional (SRL 131, PNL 76-68, MCC 76-68, SRL TDS 131, AVM-Ml à M7), vidros fabricados pela técnica sol-gel (TDS 211), vidros de alto teor de sílica (CU PGM), synroc-D, cerâmicas manufaturadas, concreto FUETAP e matrizes metálicas. Os valores obtidos são similares àqueles obtidos com os melhores vidros borosilicato presentemente usados. / We present a study of the sinterization and of the leaching behavior of a high silica porous glass matrix containing 20 weight % of simulated solution of high level liquid nuclear waste of the type Savanah River Laboratory. The porous matrix has been prepared after heat treatment of a 65% SiO2-27%B2O3-8%Na2O glass, phase separate at 560°C for 20 hours and leached in 3N HCl at 90°C. The pore size (typically 100-250Å in diameter) has been determined by the BET method. After sinterization in air at 1300°C, the samples have been physically and chemically characterized during 28 days using the MCC1, Estagnant and Soxhlet (MCC5) standard tests. We have determined thetotal weight loss, the pH, the diferential leaching rate and the cumulative concentrations for the following elements: Si, Na, B, Ca, Mn, Al, Fe and Ni by ICP technique, for Na flames spectroscopy. The results are compared with these obtained with other reference borosilicate glasses made by conventional fusion techniques (SRL 131, PNL 76-68, MCC 76-68, SRL TDS 131, AVM-M1 to M7), glasses made by sol-gel technique (TDS-211), porous glasses matrix (CU PGM), synroc-D, tailored ceramics, FUETAP concrete and metallic matrix. The values obtained are similar to those found for the best borosilicate glass presently used.

Apresentamos um estudo de solidificaçaõ e lixiviacão de matrizes de vidros porosos de alto teor de sílica armazenando 20% em peso de solução aquosa simuladora de rejeitos nucleares de alto nível de radioatividade do tipo Savanah River Labratory. A matriz porosa foi preparada após o tratamento térmico de um vidro de 65% SiO2-27%B2O3-8%Na2O, que sofreu separação de fase à 560°C por 20 horas e lixiviado em HCl - 3N à 90°C. O tamanho dos poros (tipicamente de 100 à 250Å de diâmetro) , foi determinado utilizando o método BET. Após sinterização à 1300°C em ar, as amostras foram caracterizadas física e quimicamente através de testes de lixiviação padronizados MCC1, Soxhlet (MCC5) e Estagnante durante cerca de 28 dias. Determinamos a perda de peso total, o pH, as taxas de lixiviação diferencial e as concentrações acumuladas para os seguintes elementos: Si, Na, B, Ca, Mn, Al, Fe e Ni com técnicas de ICP e espectroscopia de chama para o caso do Na. Os resultados são comparados com os obtidos com vidros borosilicatos de referência, fabricados por fusão convencional (SRL 131, PNL 76-68, MCC 76-68, SRL TDS 131, AVM-Ml à M7), vidros fabricados pela técnica sol-gel (TDS 211), vidros de alto teor de sílica (CU PGM), synroc-D, cerâmicas manufaturadas, concreto FUETAP e matrizes metálicas. Os valores obtidos são similares àqueles obtidos com os melhores vidros borosilicato presentemente usados. / We present a study of the sinterization and of the leaching behavior of a high silica porous glass matrix containing 20 weight % of simulated solution of high level liquid nuclear waste of the type Savanah River Laboratory. The porous matrix has been prepared after heat treatment of a 65% SiO2-27%B2O3-8%Na2O glass, phase separate at 560°C for 20 hours and leached in 3N HCl at 90°C. The pore size (typically 100-250Å in diameter) has been determined by the BET method. After sinterization in air at 1300°C, the samples have been physically and chemically characterized during 28 days using the MCC1, Estagnant and Soxhlet (MCC5) standard tests. We have determined thetotal weight loss, the pH, the diferential leaching rate and the cumulative concentrations for the following elements: Si, Na, B, Ca, Mn, Al, Fe and Ni by ICP technique, for Na flames spectroscopy. The results are compared with these obtained with other reference borosilicate glasses made by conventional fusion techniques (SRL 131, PNL 76-68, MCC 76-68, SRL TDS 131, AVM-M1 to M7), glasses made by sol-gel technique (TDS-211), porous glasses matrix (CU PGM), synroc-D, tailored ceramics, FUETAP concrete and metallic matrix. The values obtained are similar to those found for the best borosilicate glass presently used.