The thesis describes the synthesis of chromatographic media using several different approaches, their characterizations and applications in liquid chromatography. The steps to achieve a separation column for a specific analyte are presented. The main focus of the study was the design of novel molecularly imprinted polymers. Attachment of monolithic polymeric substrates to the walls of fused silica capillaries was studied in Paper I. With a broad literature survey, a set of common methods were tested by four techniques and ranked by their ability to improve anchoring of polymers. The best procedure was thus used for all further studies. Synthesis of monoliths in capillary columns was studied in Paper II. With the goal of separating proteins without denaturation, various monoliths were polymerized in situ using a set of common monomers and cross-linkers mixed with poly(ethylene glycol) as porogen. The resulting network was expected to present “protein-friendly pores”. Chemometrics were used to find and describe a set of co-porogens added to the polymerization cocktails in order to get good porosity and flow-through properties. Assessment of the macroporous structure of a monolith was described in Paper III. An alternative method to mercury intrusion porosimetry was proposed. The capillaries were embedded in a stained resin and observed under transmission electron microscope. Images were then computed to determine the pore sizes. Synthesis of molecularly imprinted polymers grafted to a core mono-lith in a capillary was described in Paper IV. The resulting material, imprinted with local anaesthetics, was tested for its chromatographic performance. Similar imprinted polymers were characterized by microcalorimetry in Paper V. Finally, imprinted monoliths were also synthesized in a glass tube and further introduced in a NMR rotor to describe the interactions between stationary phase and template in Paper VI.

La fatigue du seuil d’endommagement laser dans la silice fondue a été largement étudiée au cours des dernières années, car ce phénomène est directement lié à la durée de vie des matériaux optiques utilisés dans des applications laser, le plus souvent à forte puissance. En effet, dans l’UV, on observe une décroissance du seuil d’endommagement laser quand le nombre de tirs laser augmente. Ce phénomène a été attribué pour ce couple longueur d’onde-matériau à des modifications laser-induites dans le matériau. Sous irradiation laser multiple à 266 nm, en utilisant des impulsions nanosecondes de densité d’énergie constante, nous avons observé que le signal de photoluminescence est modifié jusqu’à l’endommagement. A partir de cela, nous proposons une nouvelle représentation des données expérimentales qui permet de prédire l’apparition d’un endommagement dans le matériau. Cette prédiction réalisée à partir du signal de fluorescence et non de la statistique d’endommagement utilisée jusque-là, permet une économie significative de surface de composant et du temps d’expérience. Afin d’étendre l’intérêt de l’étude à un plus grand nombre d’applications, une extension des résultats à la longueur d’onde de 355 nm est proposée. Nous proposons un modèle où l’endommagement dans la silice fondue sous irradiation multiple à 266 nm est causé par une accumulation de modifications laser-induites induisant de l’autofocalisation non-linéaire. Afin d’essayer de généraliser la méthode de diagnostic de la fatigue par fluorescence, nous avons aussi réalisé des tests préliminaires sur des cristaux optiques non-linéaires bien connus comme le LBO ou le KDP. / Fatigue effects in fused silica have been largely studied in the past years, as this phenomenon is directly linked to the lifetime of high power photonic materials. Indeed, in the UV regime, we observe a decrease of the LIDT (Laser-Induced Damage Threshold) when the number of laser shots increases and this has been attributed for this couple wavelength/material to laser-induced material modifications. Under 266 nm laser irradiation, with nanosecond pulses of constant fluence, we observed that the photoluminescence is modified until damage occurs. Based on this observation, we propose a new representation of the experimental S-on-1 breakdown data which allows predicting the occurrence of material breakdown. This prediction, based on fluorescence signal and not damage statistics (presently widely used) allows consuming fewer sample surface and saving time. To extend the interest of the study to many more applications, we propose an extension of the results at 355 nm. We suppose that damage is caused in our fused silica samples by accumulation of laser-induced modifications under multiple-pulse UV irradiation inducing catastrophic non-linear self-focusing. In order to try to extend the fatigue diagnostic method by fluorescence, we have also realized preliminary tests in well-known non-linear crystals like LBO and KDP.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-27T12:33:46Z No. of bitstreams: 1 fernandoantoniosimasvaz.pdf: 40063052 bytes, checksum: f272ddc4d930b7d243c50223436e02b2 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-13T13:00:49Z (GMT) No. of bitstreams: 1 fernandoantoniosimasvaz.pdf: 40063052 bytes, checksum: f272ddc4d930b7d243c50223436e02b2 (MD5) / Made available in DSpace on 2017-05-13T13:00:49Z (GMT). No. of bitstreams: 1 fernandoantoniosimasvaz.pdf: 40063052 bytes, checksum: f272ddc4d930b7d243c50223436e02b2 (MD5) Previous issue date: 2011-07-22 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Nesta tese é descrita a preparação de novas fases estacionárias monolíticas (FEM) polimerizadas por fotoiniciação, através do método sol-gel, em capilares de sílica fundida revestidos com poliacrilato, para aplicação em eletrocromatografia capilar (ECC). Dentre as principais técnicas de separação em Química Analítica, a ECC tem despertado grande interesse no meio acadêmico, pelo fato desta combinar as vantagens tanto da cromatografia a líquido de alta eficiência quanto da eletroforese capilar. Grande parte do desenvolvimento da ECC se deve ao uso das FEM, as quais são semelhantemente aplicadas em outras técnicas cromatográficas. Ao contrário do revestimento de poliimida, amplamente empregado, o revestimento de poliacrilato, transparente acima de 370 nm e à luz visível, facilita a visualização da solução de sol no interior do capilar, o que permite controlar a injeção desta e de outras soluções, bem como observar a formação in situ da FEM. Além disso, é possível que seja feita a polimerização fotoiniciada sem a necessidade de remoção do revestimento polimérico que protege a coluna. O objetivo central deste trabalho foi entender e aprimorar o processo de fabricação das FEM para aplicações em ECC. Para isso, foram feitas modificações da câmara fotorreatora homemade utilizada para a polimerização das FEM, como uma correção na faixa espectral de trabalho de 350 a 700 nm para 350 a 400 nm; e instalação de dispositivos de segurança tanto para o operador quanto para o sistema elétrico. Para que fosse alcançado um melhor controle de injeção de fases líquidas no interior de tubos com dimensões capilares, a construção de um dispositivo de alta pressurização (DAP) que forneceu, além da pressão, grande precisão foi indispensável. O DAP, além de simples, teve ótima relação custo-benefício, comparado a modelos comerciais. O preparo das FEM foi otimizado mediante auxílio de planejamento fatorial fracionário 24-1, onde se buscou analisar propriedades eletrocromatográficas frente diferentes proporções dos reagentes empregados e tempo de incidência de luz ultravioleta (UV). Este último fator não apresentou significância e foi desconsiderado, de forma que o planejamento fosse devidamente reduzido para um planejamento fatorial completo 23, o que possibilitou uma análise mais apurada dos efeitos significativos. O fator mais influente foi a proporção de porogênio (tolueno), sendo que a melhor condição obtida foi utilizando 80,0 % (v/v) de solução porogênica; 3,5 % (m/m) de fotoiniciador óxido de bis(2,4,6-trimetilbenzoil)-fenilfosfino (Irgacure 819); razão molar água/ metacriloxipropiltrimetoxisilano (MPTMS) igual a 4 e tempo de incidência de luz UV de 10 minutos. As características morfológicas, espectroscópicas e porosidade foram avaliadas através de microscopia eletrônica de varredura, infravermelho e porosimetria por adsorção de nitrogênio, respectivamente. As FEM foram testadas em ECC pela separação de hidrocarbonetos policíclicos aromáticos (naftaleno, acenafteno, fluoreno, fenantreno e antraceno) e alquilbenzenos (etilbenzeno, propilbenzeno, butilbenzeno e hexilbenzeno), todos compostos eletricamente neutros, diluídos em metanol (1 mmol L-1 cada), utilizando tiouréia como marcador de fluxo. Como fase móvel foi utilizada a mistura de acetato de amônio 16,7 mmol L-1 pH 7,0 (60 %) e acetonitrila (40 %). A voltagem aplicada foi -20 kV; a temperatura de análise foi 20 ºC; a injeção dos analitos foi -25 mbar por 5 s; e a detecção no UV foram nos comprimentos de onda de 220 nm e 250 nm. Foi utilizado o modo ECC-rápida, que consiste na inversão do sentido de análise e injeção de padrões pela extremidade curta do capilar. Este modo se mostrou muito mais rápido, repetitivo e eficiente do que o modo normal, fornecendo em pouco mais de 12 minutos de análise, mais de 51400 pratos/m de coluna e desvios padrão relativos em tempo de migração/retenção entre 0,09 e 3,3 % e em área de pico relativa entre 0,14 e 1,6 %. Os perfis de separação em ECC corroboraram com os resultados de porosidade e morfologia obtidos. / This thesis describes the preparation of new monolithic stationary phases (MSP) polymerized by photoinitiation through sol-gel approach in polyacrylate-coated fused silica capillary, for application in capillary electrochromatography (CEC). CEC has been concentrated much attention among the major separation techniques in analytical chemistry because it combines the advantages of both high performance liquid chromatography and capillary electrophoresis. Much of the CEC development is due to the use of MSP, which are similarly applied to other chromatographic techniques. Unlike polyimide-coating, widely used, the polyacrylate-coating, which is transparent above 370 nm and visible, enables the visualization of the sol solution within the capillary, allowing one to control the injection of sol and other solutions, in addition to observe the in situ formation of the MSP. Furthermore, it is possible to perform the photoinitiated polymerization without removing this polymeric coating that protects the capillary. The main purpose of this work was to comprehend and improve the fabrication process of MSP, for CEC applications. For this, some changes were set in the homemade photo reactor chamber, used for the MSP polymerization, like correction in the work range from 350 – 700 nm to 350 – 400 nm; and installation of security devices for both operator and electric system safeties. For better control of liquid phases injection within tubes with capillary dimensions, the build of a high-pressure device (HPD) that provides a great precision, in addition to the high-pressure, was essential. HPD is simpler and relatively cheaper when compared to commercial models. The preparation of the MSP has been optimized through assistance of a 24-1 fractional factorial design, with the intention to investigate electrochromatographic properties with different amounts of employed reagents and ultraviolet (UV) light incidence time. The later factor did not show significance and was unconsidered, making the design possible to be reduced to a 23 complete factorial design, which allowed analyzing the significant effects accurately. The most influent factor was the porogen (toluene) proportion, and the best condition was obtained using 80.0 % (v/v) of porogenic solution; 3.5 % of photoinitiator bis(2,4,6 trimetylbenzoyl)-phenylphosphine oxide (Irgacure 819); water to metacryloxypropyltrimethoxysilane (MPTMS) molar ratio equal to 4 and 10 minutes of UV light incidence time. The MSP morphological, spectroscopic characteristics and porosity were evaluated through scanning electron microscopy, infrared spectroscopy and nitrogen adsorption porosimetry, respectively. The MSP has been tested in CEC through the separation of polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, fluorene, phenanthrene and anthracene) and alkylbenzenes (ethylbenzene, propylbenzene, butylbenzene and hexylbenzene), which are electrically neutral compounds, after dilution in methanol (1 mmol L-1 each), using thiourea as the flow marker. As mobile phase a mixture of ammonium acetate 16.7 mmol L-1 at pH 7.0 (60.0 %) and acetonitrile (40.0 %) was used. The applied voltage was -20 kV, the temperature of analysis was 20 °C, the analyte injection was -25 mbar for 5 s, and UV detection was done at 220 and 250 nm. A fast-CEC mode, which consists to reverse the analysis direction and to introduce the analyte by capillary short-end injection, was performed. This mode was much more fast, repetitive and efficient than the normal one, providing in a little more than 12 minutes over than 51400 plates per meter of column and relative standard deviations ranging from 0.09 to 3.3 % for migration/retention time and from 0.14 to 1.6 % for relative peak area. The separation profiles in CEC corroborate with the porosity and morphology results.

Le collage par adhérence moléculaire est un collage basé sur la mise en contact de deux surfaces sans l'utilisation de colle ou matériaux additionnels. Ce procédé de collage est utilisé dans de nombreuses applications, notamment dans les domaines de l'optique terrestre et spatiale. Bien qu'un prototype ait déjà passé avec succès l'environnement spatial - où les contraintes d'utilisations sont différentes de celles rencontrées sur Terre - la spatialisation de cette technologie nécessite une caractérisation plus fine du procédé ainsi qu'une amélioration de la tenue mécanique des interfaces adhérées afin de valider les normes de l'Agence spatiale Européenne. Pour répondre à cette problématique de spatialisation de la technologie, des essais mécaniques ainsi que des analyses chimiques ont été réalisés dans le but d'étudier l'influence de certains paramètres du procédé ) sur la tenue mécanique et l'énergie de collage. Ces essais ont également été réalisés afin de comparer les deux matériaux étudiés : le verre de silice et le Zérodur vis-à-vis de l'adhésion. A l'issue de ces essais, les paramètres à appliquer permettant de doubler la tenue mécanique des interfaces adhérées ont été déterminés. Parallèlement, une loi phénoménologique reliant l'énergie de collage aux précédents paramètres du procédé a été développée ainsi qu'un modèle macroscopique visant à décrire l'intensité d'adhésion. Ces deux modèles une fois couplés permettent de modéliser le comportement normal de l'interface en fonction des paramètres du procédé. Enfin, ces deux lois sont implémentées dans un code éléments finis afin de simuler la propagation de la fissure lors de l'essai de clivage au coin. / Direct bonding consists in joining two surfaces without the use of any adhesive or additional material. This process is used in several applications, particularly in terrestrial and spatial optics. Although a prototype passed with success spatial environment - where constraints involved are very different from those encountered on Earth - this technology requires a more detailed characterization and an improvement of the mechanical strength of bonded interfaces in order to validate the European Space Agency standards. To address this issue, mechanical tests (double shear tests, cleavage tests and wedge tests) and chemical analysis (wetting tests and XPS spectroscopy) were performed in order to study the influence of some process parameters (roughness, relative air humidity during room temperature bonding, the annealing temperature and time) on the mechanical strength and the bonding energy. These tests compared the two materials used: fused silica glass and Zerodur glass. As a result of these tests, optimal parameters doubling the mechanical strength were also obtained. In the same time, a phenomenological law relating the bonding energy to the previous parameters is developed as well as a macroscopic model to describe the adhesion intensity. Both models when coupled describe the normal behavior of the bonded interface depending on the process parameters. Then, the both laws are implemented in a finite elements model in order to simulate the crack propagation during the wedge test.

Dans le domaine du spatial, des sources laser à forte puissance sont déjà employées dans le cadre d’activités scientifiques. On peut citer par exemple l’analyse à distance de la composition chimique des roches sur Mars par LIBS (Laser Induced Breakdown Spectroscopy) et le sondage atmosphérique par Lidar (Light Detection And Ranging) pour l’amélioration des prédictions météorologiques. Cependant l’endommagement laser (LID) et la contamination induite par laser (LIC) sur les composants optiques des systèmes demeurent des risques difficiles à anticiper. En ce qui concerne la LIC, l’interaction du flux laser avec les optiques de l’instrument en orbite peut provoquer des dégradations irréversibles, liées à la création de dépôts organiques absorbants qui peuvent induire des endommagements laser dans le temps. L’effet LIC reste donc aujourd’hui un obstacle au développement de sources laser de puissance pour les applications sans maintenance possible et possédant des durées de vie raisonnables. Une étude paramétrique de l’effet LIC est proposée dans cette thèse afin de progresser dans la compréhension des mécanismes mis en jeu / Since their first implementation in satellite systems, lasers have proven to be very versatile devices in space applications. They are key components of a variety of space-based instruments performing altimetry, light detection and ranging, laser sensing, and laser communication. However, laser induced damage (LID) and laser-induced contamination (LIC) of optical surfaces are a major failure risk for space-bound laser instruments. Regarding the LIC effect, the interaction of the laser with slight traces of organic compounds on the optical surface leads to the formation of a highly absorbing nanometric deposit on the laser footprint. Under certain conditions, this deposit may cause laser induced damage. Today, mainly the LIC effect remains an obstacle for the development of reliable and long-living spaceborne lasers. A parametric study concerning this effect was carried out in this work in order to enhance our understanding of the various mechanisms involved

L'existence des ondes gravitationnelles (OG) est l'une des prédictions les plus intéressantes de la théorie de la Relativité Générale d'Einstein. La découverte expérimentale des OG serait donc un test important de la théorie elle-même et permettra d'ouvrir une nouvelle fenêtre d'observation en particulier dans les régions de l'Univers inaccessible à l'observation électromagnétique. Les détecteurs interférométriques, comme Virgo, sont les dispositifs les plus prometteurs pour la détection d’OG. Actuellement, leur sensibilité n'est pas encore suffisante pour avoir un taux d'observation de quelques événements/an. Un intense programme expérimental pour l’améliorer est en cours. Particulièrement, les prochaines générations de détecteurs d'OG, aux basses fréquences, seront limitées par l'effet de la pression de radiation (PR) sur les miroirs suspendus. Ce phénomène, pas encore observé expérimentalement, est l'objet d'un champ de recherche très actif. Mon travail ici présenté vise à la construction d'un détecteur pour l'étude des effets quantiques de la PR dans les détecteurs d’OG: QuRaG. Il sera constitué d'un interféromètre de Michelson suspendu dont chaque bras sera une cavité Fabry-Pérot de très haute finesse, dans laquelle seulement le miroir de fond sera suspendu et sensible au bruit quantique de la PR. Durant ma thèse j'ai participé activement au R&D de tous les sous-systèmes de QuRaG. Par conséquent, le travail que j'ai fait porte sur divers aspects du projet dont les problématiques appartiennent à différents domaines de la physique. Mon travail présenté ici démontre que QuRaG sera réalisable et qu’il observera le bruit de la PR dans la bande de fréquences attendue. / The existence of gravitational waves (GW) is one of the most interesting predictions of the theory of general relativity of Einstein. The experimental discovery of GW would be an important test of the theory itself. In addition, the detection of GW will open a new window of observation especially in those regions of the Universe inaccessible to electromagnetic observations. Interferometers, as Virgo are the most promising devices for the detection of GW. Currently, the sensitivity of these detectors is not yet sufficient to have a detection rate of few events/year. Therefore, an intense experimental program to improve the sensitivity is underway. Specifically, the sensitivity of the next generations of GW detectors, at low frequencies, will be limited by the effect of the radiation pressure (RP) on the suspended mirrors. This phenomenon not yet observed experimentally in the ground based GW detectors band, is currently the subject of a very active research field. My work presented here aims at building a detector for studying quantum effects of RP in GW detectors: the QuRaG experiment. It will consist of a suspended Michelson interferometer where each arm will be a high finesse Fabry-Pérot cavity, in which only the end mirror will be further suspended and then sensitive to the RP noise. During my PhD I have actively participated to the R&D of all QuRaG subsystems. Therefore, the work that I have done deals with various aspects of the project whose related problems belong to different domains of physics. My work described in this manuscript demonstrates that QuRaG is realizable and that it will be able to observe the RP noise in the expected frequency range.

Although amorphous dielectrics feature localized states in the conduction band, electrons excited by highly intense laser radiation are usually considered as nearly free. However, localized or nearly free electrons would result in significantly different optical properties of the material. Therefore, this thesis investigates the transient complex refractive index of amorphous fused silica during the interaction with ultrashort pulsed laser radiation by applying spectroscopic imaging pump-probe ellipsometry. A Drude model, describing the excited electrons as a nearly free electron gas, and a Lorentz model, which considers the excited electrons as bound in localized states, are then approximated to the measured transient complex refractive index. The Lorentz model replicates the experimental data very well in the considered temporal range up to 200 fs after irradiation, whereas the Drude model significantly differs. Hence, the electrons are excited into localized states first, and are not describable as nearly free upon irradiation. / Obwohl amorphe Dielektrika lokalisierte Zustände im Leitungsband aufweisen, werden Elektronen, die durch hoch intensive Laserstrahlung angeregt werden, üblicherweise als quasifrei betrachtet. Im Gegensatz zu quasifreien Elektronen würden lokalisierte Elektronen jedoch zu deutlich anderen transienten optischen Eigenschaften des Materials führen. Daher wird in dieser Arbeit der transiente komplexe Brechungsindex von amorphem Quarzglas während der Wechselwirkung mit ultrakurz gepulster Laserstrahlung mittels spektroskopischer, abbildender Pump-Probe Ellipsometrie untersucht. Jeweils ein Drude-Modell, das die angeregten Elektronen als ein quasifreies Elektronengas beschreibt, und ein Lorentz-Modell, welches die angeregten Elektronen als in lokalisierten Zuständen gebunden betrachtet, werden anschließend mit dem gemessenen transienten komplexen Brechungsindex verglichen. Das Lorentz-Modell repliziert die experimentellen Daten im betrachteten Zeitbereich bis zu 200 fs nach der Bestrahlung sehr gut, während das Drude-Modell deutlich abweicht. Demnach werden die Elektronen zunächst in lokalisierte Zustände angeregt und können während und kurz nach der Bestrahlung nicht als quasifrei beschrieben werden.

With the increasing importance of hand-held devices with touch displays, the need for flat panel displays (FPDs) will likely increase in the future. Glass is the most important substrate for FPD manufacturing, where both its bulk and surface properties are critical for its performance. Many properties of the glass used in FPDs are controlled by its surface chemistry. Surface hydroxyls are the most important functional groups on a glass surface, which control processes that occurs on oxide surfaces, including wetting, adhesion, electrostatic charging and discharge, and the rate of contamination. In this dissertation, I present a new approach for determining surface silanol densities on planar surfaces. This methodology consists of tagging surface silanols using atomic layer deposition (ALD) followed by low energy ion scattering (LEIS) analysis of the tags. The LEIS signal is limited to the outermost atomic layer, i.e., LEIS is an extremely surface sensitive technique. Quantification in LEIS is straightforward in the presence of suitable reference materials. An essential part of any LEIS measurement is the preparation and characterization of the sample and appropriate reference materials that best represent the samples. My tag-and-count method was applied to chemically and thermally treated fused silica. In this work, I determined the silanol density of a fully hydroxylated fused silica surface to be 4.67 OH/nm2. This value agrees with the literature value for high surface area silica powder. My methodology should be important in future glass studies. Surface Science Spectra (SSS) is an important, peer-reviewed database of spectra from surfaces. Recently, SSS has been expanding to accept spectra from new surface techniques. I created the first SSS submission form for LEIS spectra (see appendix 5), and used it to create the first SSS LEIS paper (on CaF2 and Au reference materials, see chapter 3). I also show LEIS reference spectra for ZnO, and copper in the appendix 1. The rest of my dissertation focuses on my chemometrics/informatics and data analysis work. For example, I showed the performance and capabilities of a series of summary statistics as new tools for unsupervised exploratory data analysis (EDA) (see chapter 4). Unsupervised EDA is often the first step in understanding complex data sets because it can group, and even classify, samples according to their spectral similarities and differences. Pattern recognition entropy (PRE) and other summary statistics are direct methods for analyzing data - they are not factor-based approaches like principal component analysis (PCA) or multivariate curve resolution (MCR). I show that, in general, PRE outperforms the other summary statistics, especially in image analysis, although I recommend a suite of summary statistics be used in exploring complex data sets. In addition, I introduce the concept of divided spectrum-PRE (DS-PRE) as a new EDA method and use it to analyze multiple data sets. DS-PRE increases the discrimination power of PRE. I have also prepared a guide that discusses the vital aspects and considerations for chemometrics/informatics analyses of XPS data along with specific EDA tools that can be used to probe XPS data sets, including PRE, PCA, MCR, and cluster analysis (see chapter 5). I emphasize the importance of an initial evaluation/plotting of raw data, data preprocessing, returning to the original data after a chemometrics/informatics analysis, and determining the number of abstract factors to keep in an analysis, including reconstructing the data using PCA. In my thesis, I also show the analysis of commercial automotive lubricant oils (ALOs) with various chemometrics techniques (see chapter 6). Using these methods, the ALO samples were readily differentiated according to their American Petroleum Institute (API) classification and base oil types: mineral, semi-synthetic, and synthetic.