The vast majority of commercial gas separation membrane systems are polymeric because of processing feasibility and cost. However, polymeric membranes designed for gas separations have been known to have a trade-off between permeability and selectivity as shown in Robeson's upper bound curves. The search for membrane materials that transcend Robeson's upper bound has been the critical issue in research focused on membranes for gas separation in the past decade. To that end, many researchers have explored the idea of mixed matrix membranes (MMMs). These membranes combine a polymer matrix with inorganic molecular sieves such as zeolites. The ideal filler material in MMMs should have excellent properties as a gas adsorbent or a molecular sieve, good dispersion properties in the polymer matrix of submicron thickness, and should form high quality interfaces with the polymer matrix. In order to increase gas permeance and selectivity of polymeric membranes by fabricating MMMs, we have fabricated mixed matrix membranes using carbon nanotubes (CNTs) and nano-sized mesoporous silica. Mixed matrix membranes containing randomly oriented CNTs showed that addition of nanotubes to a polymer matrix could improve its selectivity properties as well as permeability by increasing diffusivity. Overall increases in permeance and diffusivity for all tested gases suggested that carbon nanotubes can provide high diffusivity tunnels in the CNT within the polymer matrix. This result agreed well with molecular simulation estimations. In order to prepare ordered CNTs membranes, we have developed a simple, fast, commercially attractive, and scalable orientation method. The oriented CNT membrane sample showed higher permeability by one order of magnitude than the value predicted by a Knudsen model. This CNT membrane showed higher selectivities for CO₂ over other gas molecules because of preferential interaction of CO₂ with the amine functionalized nanotubes, demonstrating practical applications in gas separations. Recently, mesoporous molecular sieves have been used in MMMs to enhance permeability or selectivity. However, due to their micrometer scale in particle size, the composite membrane was extremely brittle and tended to crack at higher silica loading. In this study, we have developed fabrication techniques to prepare MMMs containing mesoporous MCM-41 nanoparticles on the order of ~50 nm in size. This smaller nanoparticle lead to higher polymer/particle interfacial area and provides opportunity to synthesize higher loading of molecular sieves in polymer matrix up to ~80 vol%. At 80 vol% of nano-sized MCM-41 silica loading, the permeability of the membrane increased dramatically by 300 %. Despite these increases in permeability, the separation factor of the MMMs changed only slightly. Therefore, these nanoscale molecular sieves are more suitable for commercialization of MMMs with very thin selective layers than are micro-sized zeolites or molecular sieves. / Ph. D.

Des matériaux hybrides organiques-inorganiques mésostructurés ont été élaborés par deux voies différentes: le procédé sol-gel et l'assemblage de « briques » hybrides moléculaires. Dans une première partie, nous nous sommes intéressés à la synthèse directe de mésoporeux cubiques monofonctionnalisés (SBA-16) par voie sol-gel. Différents groupements organiques ont été insérés dans les pores du matériau (SH, CN, Cl, PO(OEt)2 et acac). Leur accessibilité a été mise en évidence par la complexation d'un lanthanide (europium) grâce aux fonctions acac, mais aussi par la croissance de nanoparticules d'or régulièrement distribuées dans les pores grâce aux groupements SH. Grâce à leur petite taille (2nm) et leur accessibilité, ces nanoparticules ont pu être utilisées en catalyse. Notre étude a ensuite été étendue aux matériaux mésoporeux bifonctionnels. La fonctionnalisation des pores et de la charpente de silices hexagonales (SBA-15) a été réalisée en une seule étape. Plusieurs fonctionnalités chimiques ont été insérées avec succès et ont permis le confinement intime de deux types de nanoparticules pouvant interagir entre-elles. Le matériau est alors qualifié d' « interactif ». Dans une dernière partie, nous avons développé une nouvelle approche de la synthèse de matériaux 3D organisés par assemblage de « cages » moléculaires hybrides (octasilsesquioxanes fonctionnalisés). Nous avons choisi des fonctions Cl, facilement convertibles en acides ou en ions et capables de s'auto-assembler par liaisons faibles (liaisons H) ou par forces coulombiennes. Nous avons également envisagé d'utiliser des « connecteurs » organiques comme le cyclame, capables de lier les différentes cages par liaison covalente et de fixer des ions métalliques. / Mesostructured hybrid materials (organic-inorganic) were prepared according two different ways: the sol-gel process on the one hand, the assembly of molecular hybrid 'bricks' on the other. In the first part, we focused on the one-pot synthesis of monofunctionalised cubic silicas (SBA-16) through the sol-gel process. Different organic functions were successfully introduced within the pores of the material (SH, CN, Cl, PO(OEt)2 and acac). Their accessibility was brought to light by complexation of lanthanide salts (europium) by acac moieties, but also by growing of gold nanoparticles within the pores, regularly distributed thanks to the SH groups. Thanks to their small size (2 nm) and their high accessibility, these supported nanoparticles could be used as catalysts. Secondly, our study was extended to bifunctional materials. 2-D hexagonal silicas (SBA-15) were functionalised by one-step synthesis within both pores and walls. Several organic groups were covalently included within the structure, which then allowed us to confine very closely two kinds of nanoparticles, able to interact between themselves at nanometric scale. The bimetallic material is consequently qualified as 'interactive'. The last part was dedicated to a new approach for the synthesis of 3-D structured materials, consisting in the assembly of hybrid molecular 'cages' (functionalised octasilsesquioxanes). Chloro terminations were chosen because of their easy conversion into acid or ionic moieties, able to self-assemble, driven by weak interactions such as H-bonds or electrostatic forces. The use of organic “linkers” such as cyclam groups was also considered to connect cages and anchor metallic ions.

L'objet de cette thèse a été l'étude de la structuration et de la fonctionnalisation de matériaux hybrides organiques-inorganiques par le procédé sol-gel.La synthèse et la caractérisation de nouvelles membranes à conduction protonique, pour pile à combustible à membrane échangeuse de protons, ont été réalisées dans la première partie. Des membranes hybrides à base de polyéthylène glycol hautement fonctionnalisées par de l'acide sulfonique ont été synthétisées et caractérisées d'un point de vue physicochimique et conductivité protonique. Elles présentent des bonnes propriétés mécaniques, une stabilité chimique suffisante et une conductivité protonique pertinente pour être utilisées comme électrolyte dans les piles à combustible à membrane échangeuse de proton.Dans une seconde partie, nous avons développé des matériaux hybrides mésoporeux et multifonctionnalisés dans les pores en présence de tensioactif de type copolymère block non-ionique (P123). Deux sondes ont été utilisées pour cette étude: la capacité d'échange protonique et le contrôle de la croissance des nanoparticules d'or dans les pores. / The aim of this work was focused on the structuration and the functionalization of organic-inorganic hybrid materials by the sol-gel process.The synthesis and characterization of new proton conductive membranes for fuel cell proton exchange membrane (PMFC), was prepared in the first part. Hybrid membranes based on polyethylene glycol highly functionalized with sulfonic acid have been synthesized and characterized through a physicochemical and proton conductivity. They have good mechanical properties, a sufficient chemical stability and a performant proton conductivity to be used as an electrolyte in fuel cell proton exchange membrane.In the second part, we have developed hybrid mesoporous materials with porous multifunctionalized in the presence of surfactant nonionic block copolymer (P123). Two probes were used for this study: the proton exchange capacity and the control of the growth of gold nanoparticles in the pores.

Certaines métalloenzymes catalysent l’oxydation de petites molécules organiques, dans des conditions douces (par activation du dioxygène à température et pression ambiante). Ce travail a pour but d’améliorer l’utilisation et l’efficacité catalytique des complexes de fer mimant cette activité.D’abord, par fonctionnalisation du ligand, un des complexes les plus efficaces pour catalyser l’oxydation de substrats aromatiques par H2O2, a pu être greffé dans des mésopores de silice. Ce matériau est utilisé comme support de catalyseur, en raison de sa grande surface spécifique et de sa chimie de surface versatile. Par ailleurs, la méthode de synthèse permet de structurer la taille des cavités formées, à l’aide d’un surfactant utilisé comme modèle. Le contrôle du nombre de sites catalytiques sur la surface est rendu possible par la procédure qui exploite le concept du pochoir moléculaire. Le confinement du catalyseur dans les pores pourrait être mis à profit pour former des produits à haute valeur ajoutée. En parallèle, ce complexe a aussi été greffé sur des billes de silices, un matériau moins élaboré pouvant être utilisé pour la dégradation de polluants. L’élaboration de ce type de catalyseurs supportés a nécessité de nombreuses caractérisations : analyses élémentaires, spectroscopies RMN, IR, XPS, UV-vis, RPE, isotherme d’adsorption d’azote, ATG, DRX sur poudre. Différentes méthodes de greffage ont été ainsi développées, et leur efficacité a été comparée. L’activité en catalyse d’oxydation de ces différents systèmes a aussi été évaluée.Concernant le développement des catalyseurs homogènes, le renforcement des positions  des pyridines du ligand a permis l’obtention de nouveaux complexes de fer, possédant une meilleure stabilité pour réaliser des réactions catalytiques en milieu homogène et des propriétés structurales, spectroscopiques, chimiques et catalytiques analogues aux complexes de la même famille.Enfin, un autre complexe de fer a été mis en jeu dans un procédé électrochimique utilisant le dioxygène en présence de protons pour catalyser l’hydroxylation de substrats aromatiques. / Some metalloenzymes catalyze oxidation of small organic molecules in mild conditions (via dioxygen activation at ambient temperature and pressure). This work aims to improve the use and catalytic efficiency of some of the iron complexes mimicking this activity.First, by ligand functionalization, one of the most efficient complexes catalyzing aromatic substrates oxidation by H2O2, was grafted in mesostructured porous silicas. This type of materials was used to support the iron catalyst, because of their large specific area, as well as their versatile surface chemistry. Furthermore, the method of synthesis allows to tune the size of cavities, through the use of surfactant as templates. Control of the number of catalytic sites on surface is made possible by the procedure that exploits the molecular stencil patterning technique. The confinement of catalyst in the pores could be implemented to form products with high added value. In parallel, this complex was also grafted in fumed silicate, a simpler material, that could be used to degradation of polluants. The development of this type of supported catalyst required many caracterisations : elemental analysis, NMR, IR, XPS, UV-vis and EPR spectroscopies, TGA, nitrogen sorption isotherms, powder X-ray diffraction. Different grafting methods have been followed, and their efficacy compared. The catalytic activity of the different systems was also evaluated.Concerning the development of homogenous catalysts, the strengthening of pyridine  positions on the ligand has allowed to obtain new iron complexes, having a better stability to realize catalytic reactions in homogenous condition, and structural, spectroscopic, chemical, catalytic properties similar to the complexes of the same family.Finally, another iron complex has been applied in an electrochemical process using dioxygen in the presence of proton to catalyze hydroxylation of aromatic substrates.

Made available in DSpace on 2014-12-17T15:42:28Z (GMT). No. of bitstreams: 1 GlauberJTF_TESE.pdf: 2011053 bytes, checksum: d21e71a60d82e3bce89064ab78884cef (MD5) Previous issue date: 2010-03-31 / The chemical recycling of polyolefins has been the focus of increasing attention owing potential application as a fuel and as source chemicals. The use of plastic waste contributes to the solution of pollution problems.The use of catalysts can enhance the thermal degradation of synthetic polymers, which may be avaliated by Themogravimetry (TG) and mass spectrometry (MS) combined techniques. This work aims to propose alternatives to the chemistry recycling of low-density polyethylene (LDPE) on mesoporous silica type SBA-15 and AlSBA-15.The mesoporous materials type SBA-15 and AlSBA-15 were synthesized through the hydrothermal method starting from TEOS, pseudobohemite, cloridric acid HCl and water. As structure template was used Pluronic P123. The syntheses were accomplished during the period of three days. The best calcination conditions for removal of the organic template (P123) were optimized by thermal analysis (TG/DTG) and through analyses of Xray diffraction (XRD), infrared spectroscopy (FT-IR), nitrogen adsorption and scanning electron microscopy (SEM) was verified that as much the hydrothermal synthesis method as the calcination by TG were promising for the production of mesoporous materials with high degree of hexagonal ordination. The general analysis of the method of Analog Scan was performed at 10oC/min to 500 oC to avoid deterioration of capillary with very high temperatures. Thus, with the results, we observed signs mass/charge more evident and, using the MID method, was obtained curve of evolution of these signals. The addition of catalysis produced a decrease in temperature of polymer degradation proportional to the acidity of the catalyst. The results showed that the mesoporous materials contributed to the formation of compounds of lower molecular weight and higher value in the process of catalytic degradation of LDPE, representing an alternative to chemical recycling of solid waste / A reciclagem qu?mica de poliolefinas tem sido foco de crescente aten??o, devido ao seu uso potencial como combust?vel e como fonte de produtos qu?micos. O aproveitamento de res?duos pl?sticos contribui para a solu??o dos problemas de polui??o. O uso de catalisadores adequados pode facilitar a degrada??o t?rmica de pol?meros sint?ticos, que pode ser avaliada por termogravimetria e espectrometria de massas. Este trabalho teve como objetivo avaliar uma alternativa de reciclagem qu?mica de polietileno de baixa densidade (PEBD) sobre s?lica mesoporosa tipo SBA-15 e AlSBA-15 utilizando termogravimetria e espectrometria de massas.Os materiais mesoporosos tipo SBA-15 e AlSBA- 15 foram sintetizados atrav?s do m?todo hidrot?rmico partindo de tetraetilortosilicato TEOS, pseudobohemita, ?cido clor?drico - HCl e ?gua destilada. Como direcionador estrutural foi utilizado Pluronic P123 (copol?mero tribloco). As s?nteses foram realizadas durante um per?odo de tr?s dias. As melhores condi??es de calcina??o para remo??o do direcionador org?nico (P123) foram otimizadas por an?lise t?rmica (TG/DTG) e atrav?s de an?lises por difra??o de raios X (DRX), espectroscopia na regi?o do infravermelho (FTIR), adsor??o de nitrog?nio e microscopia eletr?nica de varredura (MEV) se verificou que tanto o m?todo de s?ntese hidrot?rmico, como tamb?m as condi??es de calcina??o baseadas nos estudos cin?ticos por termogravimetria (TG) foram promissores ? produ??o de materiais mesoporosos com alto grau de ordena??o hexagonal. Os estudos de decomposi??o e evolu??o de gases foram realizados em uma termobalan?a acoplada a um espectr?metro de massas. A an?lise geral das amostras com o m?todo de Scan Analog foi realizada a 10?C/min at? 500?C para n?o deteriorar o capilar com temperaturas muito altas. Assim, com os resultados foi poss?vel observar os sinais massa-carga mais evidentes e, empregando o m?todo MID, foi obtida a curva de evolu??o desses sinais. A adi??o de catalisadores produziu uma diminui??o na temperatura de degrada??o do pol?mero proporcional ? acidez do catalisador. Os resultados obtidos, mostraram que os materiais mesoporosos contribu?ram para a forma??o de compostos de menor massa molecular e maior valor agregado no processo de degra??o catal?tica do PEBD, representando uma alternativa de reciclagem qu?mica destes res?duos s?lidos

Cette étude concerne le développement d’un dispositif innovant de type biocapteur, pour le diagnostic et le traitement local de cancers précoces. Cette technologie vise à diagnostiquer au plus tôt certains cancers, afin de les traiter de façon beaucoup plus efficace, en comparaison avec les techniques actuelles, souvent longues et mutilantes. Des microplots de silice mésoporeuse, fonctionnalisés azotures, sont déposés par impression jet d’encre (IJP) à la surface de fibres optiques. Le matériau présente une porosité auto-organisée, grâce au mécanisme d’auto-assemblage induit par évaporation (EISA). Par la suite, les microplots azotures sont fonctionnalisés spécifiquement par chimie click (click chemistry) par reaction avec des molécules alcynes. Dans le cas du diagnostic, cette fonctionnalisation permet le greffage de protéines et d’anticorps capables de reconnaître les marqueurs surexprimés à la surface des cellules cancéreuses. Les protéines et anticorps sont préalablement marqués par des fluorochromes, pour induire un transfert d’énergie (effet FRET ou Fluorescence Resonance Energy Transfer) lors de la reconnaissance des marqueurs cancéreux. Le principe de détection du dispositif repose ainsi sur une modification de la signature de fluorescence. Dans le cas de la thérapie, des photosensibilisateurs (PS) sont greffés sur les microplots pour permettre un traitement local par photothérapie dynamique (PDT).L’objectif global de l’étude vise à améliorer la sensibilité de détection du dispositif pour le diagnostic et à montrer l’efficacité de traitement dans le cas de la thérapie. Pour cela, les protocoles de réaction click et de greffage des protéines ont été optimisés et l’influence de la structuration de la porosité a été étudiée. Enfin, la sensibilité du dispositif a été caractérisée en fonction de plusieurs paramètres (type de matériaux, type de cellules cancéreuses, etc.). / This study focuses on the development of a new biosensor device for the diagnosis and local treatment of precocious tumors. This technology aims to diagnose cancers at an early stage to increase the treatment efficiency compared to existing techniques that are usually damaging. Mesoporous silica microdots with azide functions are deposited onto the surface of optical fibers using the inkjet-printing (IJP) process. The material shows a self-organized porosity, due to the evaporation-induced self-assembly (EISA) mechanism. Then, the azide microdots can be further functionalized specifically using click chemistry by reaction with alkyne precursors. For the diagnosis, the functionalization allows the grafting of proteins and antibodies capable of recognizing the increase in marker concentration at the surface of cancerous cells. These proteins and antibodies are labelled with fluorophores to induce a fluorescence energy transfer (FRET, Fluorescence Resonance Energy Transfer) with the recognition of tumorous markers. The detection principle is based on the modification change of the fluorescence signature. For the therapy, photosensitizers (PS) are anchored onto the microdots to allow the local treatment using photodynamic therapy (PDT). The main aim of this study was to optimize the device sensitivity concerning the diagnosis step, and to show the treatment efficiency concerning the therapy step. On that purpose, the protocols of click reaction and the grafting of proteins have been optimized, which are also influenced by the porosity organization that has been studied. Finally, the device sensitivity has been characterized as a function of multiple factors (materials, cancer cells type, etc.).

Orientador: Devaney Ribeiro do Carmo / Resumo: O presente trabalho descreve a preparação de materiais porosos (MCM-41 e Zeólita FAU) inorganofuncionalizados com Titânio e Zircônio e subsequente modificação química com hexacianoferrato de níquel. Os materiais preparados foram caracterizados empregando diferentes técnicas: Espectroscopia na Região do Infravermelho por transformada de Fourier (FTIR), Ressonância Magnética Nuclear (RMN), Difração de Raios-X (DRX), Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva de Raios-X (EDX), Análise Termogravimétrica (TGA), Porosidade e Área superficial. Após a obtenção dos materias (MTiNiH, MZrNiH, ZTiNiH e ZZrNiH), realizou-se um estudo sistemático sobre o comportamento voltamétrico desses materiais, empregando a técnica de Voltametria Cíclica (VC) e eletrodos de pasta de grafite. O voltamograma cíclico dos materiais MTiNiH e ZTiNiH exibiram um par redox bem definido com Eθ’= 0,49 V e os eletrodos de pasta de grafite modificados com MZrNiH e ZZrNiH exibiram um par redox com Eθ’= 0,50 V, atribuídos ao processo Fe(II)/Fe(III) em presença de níquel (II). Os eletrodos de pasta de grafite modificados com os materiais citados anteriormente mostraram-se sensível a concentrações de isoniazida e sulfito, sendo que apresentaram melhores desempenhos na eletro-oxidação catalítica da isoniazida. Após os testes de eletro-oxidação catalítica dessas substâncias, realizou-se uma investigação da influência dos principais interferentes, de forma que a interferência observad... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present work describes the preparation of porous materials (MCM-41 and FAU Zeolite) inorganofunctionalized with Titanium and Zirconium and subsequent chemical modification with nickel hexacyanoferrate. The prepared materials were characterized using different techniques: Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), Thermogravimetric Analysis (TGA), Porosity and Surface Area. After obtaining the materials (MTiNiH, MZrNiH, ZTiNiH and ZZrNiH), a systematic study on the voltammetric behavior of these materials was performed using the Cyclic Voltammetry technique (CV) and modified graphite paste electrodes. The cyclic voltammogram of the MTiNiH and ZTiNiH materials exhibited a well-defined redox pair with Eθ’ = 0.49 V whereas the MZrNiH and ZZrNiH modified graphite paste electrodes exhibited a redox pair with Eθ’ = 0.50 V, all of them being assigned to the redox process Fe(II)/Fe(III) in the presence of nickel (II). The graphite paste electrodes modified with the aforementioned materials were sensitive to isoniazid and sulfite concentrations, and showed greater performance in the catalytic electrooxidation of isoniazid. After the catalytic electro-oxidation tests of these substances, the influence of the main interferents was investigated and so the observed interference was not significant for isoniazid. Recovery of these substances fro... (Complete abstract click electronic access below) / Doutor

Choosing the right solvent is critical for many industrial applications. A useful property for selection of solvents is their solubility parameters. This concept of solubility parameters is central to this thesis and has been used in two different case studies of material treatment applications. Silicone rubber (crosslinked poly(dimethyl siloxane), PDMS) has many favorable material properties making it useful in biomedical devices. However, a limiting aspect of its material properties is a hydrophobic surface. The aim of this work was to prepare a hydrophilic PDMS material while retaining the transparency of the material. To do this, PDMS was combined with a hydrophilic polymer, polyvinylpyrrolidone (PVP) in an interpenetrating polymer network (IPN). A two-step IPN synthesis method was developed and it was found that the solvent used for polymerization of PVP had a significant influence on the water-wettability and the transparency of the PVP/PDMS IPN. Several different analytical techniques were used for determining the degree of phase separation in the PVP/PDMS IPN. It was found, by using microscopy techniques, that the PVP phase domains varied between 200 nm up to a few micrometers, and the size of the phase domains was correlated to the solvent used for polymerization of the IPN. The second topic for which solvent effects were explored was for the use of mesoporous silica particles as potential drug delivery devices. In the present work a drug molecule, ibuprofen, was loaded into mesoporous silica particles using different solvents, and in addition adsorption isotherms were established in each solvent. The maximum loading of ibuprofen in the mesoporous material was achieved when using a nonpolar solvent, in particular liquid carbon dioxide was successfully used. One of the advantages of using liquid carbon dioxide is that no solvent residues are left in the final material, which is important for pharmaceutical applications. Furthermore, it was concluded that ibuprofen was stored in an X-ray amorphous form in the mesoporous particles. Release studies in water showed a rapid release of ibuprofen from the mesoporous silica particles, while the dissolution of samples with crystalline ibuprofen was slower. This was verified to be an effect of a larger exposed ibuprofen area in the ibuprofen-loaded mesoporous silica particles, and it was concluded that the intrinsic dissolution rate for the samples were identical.

Orientador: Prof. Dr. Sergio Brochsztain / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2016. / O presente trabalho visa à utilização de materiais mesoporosos funcionalizados com imidas aromáticas em algumas importantes aplicações do setor energético. Os materiais são constituídos de silicatos (SiO2) mesoporosos com a imida aromática 1,8-naftalimida (NI) ligada covalentemente às paredes dos poros, formando assim um composto híbrido com alto nível de organização. A primeira aplicação destes materiais está relacionada à captação de luz e transferência de energia entre cromóforos localizados no interior destas sílicas. Para isto, o cromóforo doador de energia foi a NI e como aceptor de energia foi a N, N- bis(2,6-dimetilfenil)¿3,4,9,10- tetracarboxilperilenodiimida (DMPDI). Através desta transferência de energia foi possível ajustar a cor de emissão de fluorescência, resultando em emissão branca, sendo interessante para aplicações em diodos emissores de luz (LEDs). Uma segunda utilização dos materiais mesoporosos realizada no presente trabalho esta relacionada à indústria do petróleo e consiste na degradação de asfaltenos através da fotocatálise heterogênea. Neste sistema, as sílicas mesoporosas funcionalizadas com a imida aromática NI foram utilizadas como compostos fotocatalisadores. Para isso, foi avaliado em um primeiro momento o desempenho destes materiais em um sistema de fotocatálise padrão constituído pelo corante azul de metileno (AM) para a subsequente aplicação na degradação dos asfaltenos. Os materiais se mostraram satisfatórios como fotocatalisadores heterogêneos, promovendo a mineralização completa do AM em cerca de 5 horas quando o sistema era irradiado com lâmpada de mercúrio. Testes preliminares mostraram que os materiais foram também efetivos na degradação de asfaltenos. / The present study has as a goal the use of mesoporous materials modified with aromatic imides for applications in the energy field. The materials consist of mesoporous silicas with 1,8-naphthalimides (NI) covalently bound to the inner pore walls. The first application tested was the potential as light harvesting materials. For this purpose, energy transfer between different chromophores within the pores was studied. For these studies, NI was used as the energy donor and N,N'-bis(2,6-dimethylphenyl)¿3,4,9,10-tetracarboxyperylenediimide (DMPDI) as the energy acceptor. It was possible to tune the color of the emission, including white emission, by adjusting the relative amount of the two imides within the pores, showing that the materials have potential applications for the construction of LEDs. A second application that was tested was the use of the mesoporous materials as photocatalysts for the degradation of petroleum asphaltenes. For this purpose, the system was initially tested with methylene blue (MB), a typical pollutant from the textile industry. Complete mineralization of MB was observed after 5 hours of irradiation with a mercury lamp, in the presence of the mesoporous materials modified with NI. Initial tests showed that the materials were also effective in the photodegradation of the asphaltenes.

Dans ce travail, plusieurs applications des films minces à base de silice mésoporeuse fonctionnalisée, générés par auto-assemblage électrochimiquement-assisté (EASA), organisés et orientés, ont été développées. Au préalable, avant de se concentrer sur les films fonctionnalisés proprement dits, nous avons caractérisé les propriétés de perméabilité de tels films vis-à-vis de sondes redox en solution différemment chargées (neutre, Fc(MeOH)2, positive, Ru(NH3)63+, négatives, Fe(CN)63-/4-), démontrant une limitation électrostatique pour les anions. Ceci nous a amené à étudier l'amplification de la réponse électrochimique des sondes électroactives anioniques (Fe(CN)63-/4-) en présence d’un film de silice chargé négativement sur la surface de l’électrode en ayant recours à des médiateurs neutres ou chargés positivement. La fonctionnalisation de ces films minces de silice a été effectuée en combinant la méthode EASA pour obtenir un film de silice fonctionnalisé par de groupements azoture avec une réaction de couplage avec un groupe alcyne (l’éthynyl-ferrocène dans ce cas). La réponse électrochimique obtenue pour ces films isolants fonctionnalisés par des groupes ferrocene électroactifs est due à un mécanisme de saut d’électrons entre les sites électroactifs adjacents. L'oxydation électrochimique du ferrocène en ion ferricinium génère des charges positives qui sont compensées par l'entrée d'anions permettant une éventuelle détection ampérométrique indirecte d'anions non électroactifs. L’injection d’anions non-électroactifs dans une cellule électrochimique constituée par une électrode de travail fonctionnalisée par ces films de silice porteurs de groupements ferrocène, soumise à l’imposition d’un potentiel positif (+0,5 V), a donné lieu à une réponse ampérométrique proportionnelle à la concentration d'anions. La régénération de l’électrode par réduction du ferricinium était nécessaire afin d’éviter la diminution du signal électrochimique dû à la consommation progressive du ferrocène par des multiples analyses successives. Cette régénération a été réalisée in situ par une méthode ampérométrique à onde carrée. Le films mésoporeux orientés peuvent également être fonctionnalisés par des complexes à base de ruthénium du type [Ru(bpy)2(bpy')]2+ en adaptant la méthode décrite auparavant. Le succès de la fonctionnalisation est vérifié par électrochimie et aussi par spectroscopie UV-Vis au travers de la bande MLCT caractéristique du complexe immobilisé. Une étude plus approfondie est effectuée lors du transfert de charge (saut d'électrons le long des sites adjacents) et le transport de masse de l’anion compensateur de charge au travers des canaux mésoporeux en faisant varier la vitesse de balayage en potentiel. Les propriétés de luminescence de ces films ont été étudiées en présence et en absence d’oxygène, évaluant la possibilité d'utiliser ce type de film pour des applications telles que l'électrochimiluminescence ou la détection d’oxygène. Finalement, ces films à base silice orientés ont été utilisés pour la croissance de nanofilaments de polyaniline (PANI). Ces nanofilaments de polyaniline ordonnée sont générés par voie électrochimique de manière contrôlée. Etant donnée la taille des mésopores (2 nm de diamètre), des chaînes PANI quasi-uniques sont vraisemblablement produites. À partir d'expériences de chronoampérométrie, sur base de films de différentes épaisseurs (100-200 nm), il est possible de prouver l’existence de plusieurs étapes d'électropolymérisation. Chaque étape de la formation du polymère (période d'induction, croissance de la polyaniline au sein et en dehors des canaux mésoporeux) est clairement identifiée. La génération de nanofilaments de polyaniline isolés est démontrée par l'amélioration de la réversibilité entre les états conducteurs et non-conducteurs de la polyaniline. La possibilité de contrôler et d'adapter la croissance des nanofilaments polymères conducteurs offre de nombreuses possibilités [...] / In this work, we exploited the vertically-aligned mesoporous silica thin films generated by electro-assisted self-assembly (EASA). First of all, we present a study about the amplification of charge transfer of a repulsed anionic redox probes [i.e. Fe(CN)63-/4-] through the negatively charged silica film by using neutrally or positively charged redox probes [Fc(MeOH)2 or Ru(NH3)63+ respectively] through redox mediating processes. Furthermore, the functionalization can be conducted by combining EASA method to obtain azide-functionalized silica film and further letting it react with an ethynyl-bearing reactant (e.g. ethynyl-ferrocene) according Huisgen click chemistry. The resulting ferrocene-functionalized silica films are electroactive, involving an electron hopping mechanism between adjacent ferrocene moieties. The electrochemical oxidation of ferrocene into ferricinium ion generates positive charges that are compensated by the ingress of anions into the film, opening the door to possible indirect amperometric detection of non-electroactive anions by flow injection analysis. Operating in an electrolyte-free flow, each injection of an anion (e.g., NO3-) at an electrode biased at a suitable positive potential (i.e., +0.5 V) gave rise to an amperometric response proportional to the anion concentration. However, to avoid the decrease of the electrochemical signal due to the progressive consumption of ferrocene in multiple successive analyses, it was necessary to regenerate the electrode by reduction of ferricinium moieties, which can be achieved in-situ by square wave amperometry. The feasibility to apply such indirect amperometric detection scheme in suppressed ion chromatography (for detecting anions in mixture) was also demonstrated. The oriented mesoporous film can also be functionalized with ruthenium(II)bipyridyl complex [Ru(bpy)2(bpy’)]2+ using the same method. Optimization of the functionalization level is controlled electrochemically by cyclic voltammetry (CV) and monitored through the UV-vis spectra. Further study is conducted upon the charge transfer (electron hopping along the adjacent sites) and the mass transfer of the compensating counter anion through the mesochannels by varying the CV potential scan rate. The emission of the [Ru(bpy)2(bpy’)]2+-functionalized film and its quenching in the presence of oxygen are evidenced in both aqueous and organic solvent, giving opportunities to apply the film for different application, such as electrochemiluminescence sensor and oxygen detection. Lastly, the vertically-aligned mesoporous silica film is used as a hard template to grow polyanilinine nanofilaments. The growth of ordered polyaniline nanofilaments is controlled by potentiostatic polymerization. In such small pore template (2 nm in diameter), quasi-single PANI chains are likely to be produced. From chronoamperometric experiments and using films of various thicknesses (100−200 nm) it is possible to evidence the electropolymerization transients, wherein each stage of polymerization (induction period, growth, and overgrowth of polyaniline on mesoporous silica films) is clearly identified. The advantageous effect of mesostructured silica thin films as hard templates for the generation of isolated polyaniline nanofilaments is demonstrated from enhancement of the reversibility between the conductive and the nonconductive states of polyaniline and the higher electroactive surface areas displayed for all mesoporous silica/PANI composites. The possibility to control and tailor the growth of conducting polymer nanofilaments offers numerous opportunities for applications in various fields including energy, sensors and biosensors, photovoltaics, nanophotonics, or nanoelectronics