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No presente trabalho foram obtidos e caracterizados filmes finos de SnO2 e SnO2:Sb preparados pelo processo sol-gel. Estes filmes foram estudados através da influência do número de camadas nas suas propriedades ótico-eletroquímicas. Foi observado que a densidade de carga para um filme de SnO2:Sb de 5 camadas foi de 40 mC/cm2, tornando-se um excelente candidato como contra-eletrodo para aplicação em janelas eletrocrômicas. Os filmes de SnO2 e SnO2:Sb também foram estudados utilizando técnicas eletroquímicas: cronoamperometria e voltametria cíclica cujo o enfoque na análise foi o de intercalação de lítio em função da carga inserida. As medidas de transmissão ótica na região de ultravioletainfravermelho próximo revelaram que estes filmes possuem leve coloração azul, evidenciadas pela mudança do espectro UV-Vis em 8% entre estado colorido e descolorido; Por espectroscopia no infravermelho dos sóis, foi possível observar bandas características dos grupos de moléculas presentes em alcóxido, confirmando a formação do alcóxido de estanho enquanto dos precipitados apenas evidências da formação do óxido de estanho. As morfologias dos filmes estudadas por Microscopia Eletrônica de Varredura (MEV) e Microscopia de Força Atômica (AFM) demonstraram que o filme apresenta pequenos riscos, provavelmente devido a presença de Sb, e por AFM obtidas informações da rugosidade e do tamanho de grão, sendo estes valores de 100 nm e 104 nm respectivamente. A partir do espectro do filme por EDX foi possível confirmar a presença de estanho e antimônio nos filmes. A estrutura dos xerogéis e dos sóis para deposição dos filmes estudada por difração de raios-X é a casseterite. Por fim Análises Térmicas (DSC/TGA) demonstram que à 60oC um pico endotérmico correspondendo à liberação de água e uma perda da massa de 6,3 %, e na faixa de 450C um pequeno aumento da linha de base no sentido exotérmico atribuído a cristalização do SnO2:Sb na fase casseterite, com perda de massa de 33%. / In this study were obtained and characterized thin films of SnO2 and SnO2: Sb prepared by the sol-gel process. These films were studied through the influence of the number of layers in its optical-electrochemical properties. It was observed that the density of charge for a film of SnO2: Sb, 5 layers was 40 mC/cm2, making it an excellent candidate as counter-electrode for use in electrochromic windows. The films of SnO2 and SnO2: Sb also were studied using electrochemical techniques: chronoamperometry and cyclic voltammetry with a focus on analysis of intercalation of lithium according to load inserted. Measures of optical transmission in the ultraviolet region of near-infrared revealed that these films have light blue colour, highlighted by the changing spectrum of UV-Vis by 8% between state and colorful discolour; In the infrared spectroscopy, in solution has been possible to see bands characteristics groups of molecules present in alkoxide, confirming the formation of alkoxide of tin while the precipitated only evidence of the formation formation of tin oxide. The morphologies of the films studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) showed that the film presents little risk, probably because the presence of Sb, and the information obtained by the AFM roughness and the size of grain, and these values of 100 nm and 104 nm respectively. From the spectrum of the film by EDX were unable to confirm the presence of tin and antimony in the films. The structure of xerogel and solution for deposition of films studied by X-rays diffraction is the cassiterite. Finally Thermal Analysis (DSC / TGA) show that the 60oC a peak endothermical corresponding to the release of water and a loss of the mass of 6.3%, and in the 450ºC a small increase from baseline in the sense attributed range of exothermically the crystallization of SnO2:Sb during casseterite, with mass loss of 33%.

No presente trabalho foram obtidos e caracterizados filmes finos de SnO2 e SnO2:Sb preparados pelo processo sol-gel. Estes filmes foram estudados através da influência do número de camadas nas suas propriedades ótico-eletroquímicas. Foi observado que a densidade de carga para um filme de SnO2:Sb de 5 camadas foi de 40 mC/cm2, tornando-se um excelente candidato como contra-eletrodo para aplicação em janelas eletrocrômicas. Os filmes de SnO2 e SnO2:Sb também foram estudados utilizando técnicas eletroquímicas: cronoamperometria e voltametria cíclica cujo o enfoque na análise foi o de intercalação de lítio em função da carga inserida. As medidas de transmissão ótica na região de ultravioletainfravermelho próximo revelaram que estes filmes possuem leve coloração azul, evidenciadas pela mudança do espectro UV-Vis em 8% entre estado colorido e descolorido; Por espectroscopia no infravermelho dos sóis, foi possível observar bandas características dos grupos de moléculas presentes em alcóxido, confirmando a formação do alcóxido de estanho enquanto dos precipitados apenas evidências da formação do óxido de estanho. As morfologias dos filmes estudadas por Microscopia Eletrônica de Varredura (MEV) e Microscopia de Força Atômica (AFM) demonstraram que o filme apresenta pequenos riscos, provavelmente devido a presença de Sb, e por AFM obtidas informações da rugosidade e do tamanho de grão, sendo estes valores de 100 nm e 104 nm respectivamente. A partir do espectro do filme por EDX foi possível confirmar a presença de estanho e antimônio nos filmes. A estrutura dos xerogéis e dos sóis para deposição dos filmes estudada por difração de raios-X é a casseterite. Por fim Análises Térmicas (DSC/TGA) demonstram que à 60oC um pico endotérmico correspondendo à liberação de água e uma perda da massa de 6,3 %, e na faixa de 450C um pequeno aumento da linha de base no sentido exotérmico atribuído a cristalização do SnO2:Sb na fase casseterite, com perda de massa de 33%. / In this study were obtained and characterized thin films of SnO2 and SnO2: Sb prepared by the sol-gel process. These films were studied through the influence of the number of layers in its optical-electrochemical properties. It was observed that the density of charge for a film of SnO2: Sb, 5 layers was 40 mC/cm2, making it an excellent candidate as counter-electrode for use in electrochromic windows. The films of SnO2 and SnO2: Sb also were studied using electrochemical techniques: chronoamperometry and cyclic voltammetry with a focus on analysis of intercalation of lithium according to load inserted. Measures of optical transmission in the ultraviolet region of near-infrared revealed that these films have light blue colour, highlighted by the changing spectrum of UV-Vis by 8% between state and colorful discolour; In the infrared spectroscopy, in solution has been possible to see bands characteristics groups of molecules present in alkoxide, confirming the formation of alkoxide of tin while the precipitated only evidence of the formation formation of tin oxide. The morphologies of the films studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) showed that the film presents little risk, probably because the presence of Sb, and the information obtained by the AFM roughness and the size of grain, and these values of 100 nm and 104 nm respectively. From the spectrum of the film by EDX were unable to confirm the presence of tin and antimony in the films. The structure of xerogel and solution for deposition of films studied by X-rays diffraction is the cassiterite. Finally Thermal Analysis (DSC / TGA) show that the 60oC a peak endothermical corresponding to the release of water and a loss of the mass of 6.3%, and in the 450ºC a small increase from baseline in the sense attributed range of exothermically the crystallization of SnO2:Sb during casseterite, with mass loss of 33%.

Supercapacitors have attracted great attention because of their high power density, long life cycle and high efficiency. They can be generally classified into two types: electrical double-layer capacitors (EDLCs) and pseudocapacitors. Compared with pseudocapacitors, EDLCs have a very fast charge/discharge rate, higher power density, higher coulombic efficiency and longer cycle life. Recently, in order to meet the requirements of portable and wearable electronics, supercapacitor development is moving towards flexible and stretchable solutions. This thesis presents the design, fabrication, performance testing and optimisation of flexible strip and fibre EDLCs. In this research, a sandwich structured strip EDLC was designed and manufactured. Experimental design was utilised to optimise the operation parameters of the EDLC in order to improve its capacity for energy storage. The flexibility of the strip EDLCs was studied extensively by mechanical tests under static and dynamic loading conditions, and the correlation between the electrochemical performance of the EDLCs and the mechanical testing process was investigated. Novel coaxial fibre EDLCs have also been studied and developed in this study. Fibre supercapacitors showed a good flexibility and weavability. The activated carbon produced by ball-milling method with optimum specific capacitance was mixed with commercial ink to produce active material to optimise the electrochemical performance of fibre EDLCs. The flexible EDLCs were applied into different appliances to demonstrate the stability of performance and the usability of EDLCs developed in this study. The electrical current and potential range can be altered by connecting multiple strip or fibre EDLCs in parallel or in series to meet the power and energy requirements. It has been proved that the flexible EDLCs developed have a great potential to be used as energy storage devices for smart electronics. This thesis makes original contributions to knowledge, including using an advanced test method to study the electrochemical performance of flexible supercapacitors under static and dynamic mechanical testing, investigation of the effect of key parameters in the manufacturing process on the performance of strip supercapacitors using experimental design method to optimise the supercapacitors’ performance, and optimisation of the performance of fibre supercapacitors by improving the structure and using a new active material with higher specific capacitance.

Electrically conductive smart textiles are a very interesting area that could be important for the development of smart textiles. Today, conductive yarns and threads are often produced from coveted metals such as silver, copper and gold. These metals require large resources to be extracted and processed into yarns and threads and have a major impact on humans and the environment. One way to reduce the consumption of metals and save resources is to coat yarns of textile materials with electrically conductive polymers. In this study, we will investigate coating yarns with the conductive polymer blend PEDOT-PSS. PEDOT-PSS is extracted from oil, which is a non-renewable raw material, but coating with this polymer dispersion has many other advantages over metals and its production chain. Like coating yarn through a chemical bath produces very little waste, the yarn has a smaller mass, the yarn becomes more flexible, and it is easy to scale up production. However, previous studies have shown that there are some difficulties when it comes to coating yarns with PEDOT-PSS. The coating becomes fragile and brittle and to some extent affects the yarn that is coated in terms of mechanical properties. In this study, its investigated how the yarn is affected by various parameters in the production line, such as drying temperature, the viscosity of the PEDOT-PSS dispersion and the speed of the thread traveling through the production line, to find optimal production parameters that provide a balance between conductive and mechanical properties. We have produced a number of samples, all with different variations of parameters, and investigated how its conductive and mechanical properties are affected to see if there is a pattern and connection between parameters and conductive and mechanical properties on the yarn. The results show that yarn samples made with high viscosity of the PEDOT-PSS dispersion are among the lower range of resistance (with some exceptions), with average values of about 2990 O up to 10300 O, while lower viscosity shows uneven results with average values of about 92,000 O and all the way up to about 6,500,000 O. Most samples with lower measured O values are made with a high drying temperature, but no clear connection could be detected between temperature and end result, nor did the different speeds show any clear connection to the result. For the mechanical properties, it turns out that there is a relationship between result and viscosity as well as result and drying temperature. Samples made with low viscosity and low drying temperature perform best in the mechanical tests, 59.7% to 52.9% elongation and 25 cN / tex to 21 cN / tex. While speeds in this category could not show any connection between the results either. Overall, the results can be summarized as the results of tests show that there are some correlations between the parameters and the properties of the yarn samples and that the viscosity of the PEDOT-PSS dispersion and drying temperature are the most influential parameters. For conductive properties, viscosity has the greatest effect and for mechanical properties, viscosity and temperature have the greatest effect. For conductive properties, high viscosity is good, and for mechanical properties, low temperature and low viscosity are best. The sample with the best combination of test results was tested in a knitting machine but the variant chosen for knitting did not have good enough mechanical properties for the knitting machine used and broke when exposed to the stress from the knitting process. Therefore, the knitting test was not successful, but it was possible to sift out what parameter of the production line that had the greatest impact on the coated yarn properties.

Yes / Dynamic wetting failure was observed in the simple dip coating flow with a series of substrates, which had a rough side and a comparatively smoother side. When we compared the air entrainment speeds on both sides, we found a switch in behaviour at a critical viscosity. At viscosity lower than a critical value, the rough side entrained air at lower speeds than the smooth side. Above the critical viscosity the reverse was observed, the smooth side entraining air at lower speed than the rough side. Only substrates with significant roughness showed this behaviour. Below a critical roughness, the rough side always entrained air at lower speeds than the smooth side. These results have both fundamental and practical merits. They support the hydrodynamic theory of dynamic wetting failure and imply that one can coat viscous fluids at higher speeds than normal by roughening substrates. A mechanism and a model are presented to explain dynamic wetting failure on rough surfaces.

Le vaporeformage du méthane (SMR) est encore aujourd’hui la méthode industrielle de synthèse d’hydrogène la plus rentable. L’efficacité globale de ce procédé est cependant limitée par les contraintes techniques intrinsèques au design des unités de production actuelles. Dans un souci constant d’intensification des procédés, des échangeurs-réacteurs intensifiés sont à l’étude chez AIR LIQUIDE. Les progrès dans le domaine des techniques de fabrication additive métallique ont permis d’envisager des unités de production sous formes d’équipements compacts, présentant des canaux millimétriques, qui optimisent les transferts de masse et de chaleur. Pour atteindre des taux de conversion élevés, et ce malgré des temps de contacts réduits, ces structures obligent à développer de nouvelles architectures de catalyseurs. Des phases actives supportées stables et très actives pour la réaction SMR à base de rhodium ont été préparés à partir de supports MgAl2O4 commerciaux. L’étude de l’impact du taux de métal noble, des propriétés des supports, ainsi que des traitements thermiques a permis de comprendre les interactions existantes entre les phases actives et les supports oxydes. Les propriétés catalytiques en condition de reformage ont pu être reliées aux morphologies des phases actives synthétisées. La fonctionnalisation des canaux des échangeurs-réacteurs millistructurés par une méthode proche du dip-coating est détaillée dans cette thèse. Des formulations de suspensions adaptées, aux comportements rhéologiques maîtrisés, ont permis avec des protocoles de dépôt adéquats, de rendre fonctionnel des échangeurs-réacteurs de taille semi-industrielle qui ont été testés avec succès durant plusieurs centaines d’heures. / The Steam Methane Reforming (SMR) process is still today the most profitable industrial synthesis process of hydrogen. The efficiency of this technique is however facing intrinsically technical limitations due to the design of production units. In order to intensify the global process, exchangers-reactors are under investigation at AIR LIQUIDE. Thanks to recent progresses in metallic additive manufacturing, new compact equipment can be designed. Structures made of millimetric channels allow optimizing heat and mass transfers. New catalyst architecture design needs to be developed to reach high conversion rates despite extreme low contact times in such devices. Stable and highly active rhodium-based catalysts supported on spinel MgAl2O4 have been prepared in this aim. The impact of rhodium loading, properties of supports, as well as thermal treatments have allowed us understanding active phase and support interactions. Catalyst properties under SMR conditions have been linked to active phase morphologies. Functionalization of exchangers-reactors channels through a dip-coating technique has been detailed in this thesis. The formulations of suspensions of washcoat have been optimized thanks to rheological behavior characterizations to achieve very low viscosities. A procedure to deposit homogeneous coatings with controlled thicknesses on the internal channels has been validated on a pilot structure. These new intensified exchangers-reactors have been successfully tested for methane conversion during several hundred of hours.

Ce travail s’intéresse a la synthèse et à la caractérisation de revêtements hybrides O/I à base de silice, préparés par voie sol-gel et déposés sur polycarbonate (PC), pour des applications en milieu chaud et humide dans le domaine culinaire. Le PC étant connu pour sa sensibilité à l’hydrolyse dans ce type de milieux (provoquant sa dépolymérisation progressive et ainsi la libération de bisphénol A, molécule suspectée comme étant toxique), le rôle du revêtement est donc de protéger le PC et d’éviter son vieillissement prématuré, tout en améliorant ses propriétés mécaniques. Dans un premier temps, de nombreux sols ont été synthétisés et optimisés, principalement en termes de nature et quantités de précurseurs, et de pH, dans le but d’obtenir des revêtements homogènes et transparents. Un suivi des réactions d’hydrolyse et de condensation des sols a également été réalisé afin de déterminer le temps minimal de maturation de ces derniers. Apres dépôt des revêtements par dip-coating, les propriétés mécaniques des films ont été étudiées par de nombreuses techniques. D’un point de vue général, les propriétés des échantillons revêtus ont été trouvées supérieures à celles du PC nu. L’influence de nombreux paramètres de synthèse comme le ratio organoalcoxysilane(s)/silice colloïdale, l’ajout d’additifs, le type de traitement de surface du PC pré-dépôt ou encore les conditions de recuit, a également été étudiée. L’ensemble de ce travail a permis d’obtenir, à partir de deux systèmes sol-gel différents, des revêtements performants en termes de transparence, d’adhésion au substrat, de non-toxicité, couplés à des valeurs élevées de dureté, de densité et de module de Young / This work deals with the synthesis and the characterization of hybrid O/I silica coatings prepared by the sol-gel route and deposited on polycarbonate (PC), for applications in hot and humid environment in the alimentary field. PC is well-known for undergoing hydrolysis in such conditions (causing its progressive depolymerization and thus leading to the release of bisphenol A, a molecule suspected to be toxic): the function of the coating would thus consist in preventing PC from this kind of premature ageing, along with the enhancement of its mechanical properties. As a first step, a lot of different sols were synthesized and optimized, mainly in terms of type and quantity of precursors, along with the pH, in order to obtain transparent and homogeneous coatings. The hydrolysis and condensation reactions were monitored in order to determine the minimum ageing time to be waited before any film deposition. After deposition by dip-coating, the mechanical properties of the films were assessed by using many different techniques. Basically, the coated-PC samples display higher properties than the uncoated one. The influence of numerous synthesis parameters such as the organoalkoxysilanes/colloidal silica ratio, the presence of additives, the kind of surface treatment of PC before film deposition, or the annealing conditions was also studied. This whole work led to the synthesis, from two different sol-gel systems, of superior quality coatings in terms of transparency, adherence to the substrate, non-toxicity, along with elevated hardness, density and Young’s modulus values

Comme les propriétés physiques d'un matériau à l’échelle nanométrique sont largement dépendantes de la taille et de la forme des nanostructures, il est inutile de synthétiser de nouvelles compositions et morphologies. L’étude avancée de leur structure par les techniques de caractérisation usuelles (MET, MEB, DRX, Raman…) permettra de collecter toutes les informations nécessaires à la compréhension de leurs propriétés physiques (magnétiques, optiques, électriques). Dans ce manuscrit, nous décrirons plusieurs approches d’élaboration de nanostructures 0D, 1D et 2D multifonctionnelles afin de mieux connaître les paramètres qui contrôlent leur composition chimique et leur structure. De plus, ce travail de recherche a abouti à la synthèse de nouveaux matériaux à base d’oxyde et de carbure de fer. Des nanofibres magnétiques ayant des morphologies originales « Ruban » et « tube » ont été élaborées par la technique d’électrospinning en modifiant plusieurs paramètres expérimentaux : concentration de la solution, atmosphères de traitement thermique, température de recuit… De plus, des couches minces guidantes dopées par des nanostructures magnétiques ont été préparées par la technique dip-coating. Nous avons mené une étude complexe et détaillée sur les propriétés structurales de ces matériaux afin de définir les paramètres expérimentaux qui permettront d’obtenir des nano objets de bonne qualité. Dans un but ultime, nous souhaiterons explorer les possibilités d’application de ces matériaux qui présentent à la fois des caractéristiques électriques et magnétiques. / The physical properties of a nanomaterial strongly depend on the size and the shape of the nanostructure. As a consequence, it is interesting to elaborate new materials with different compositions and morphologies. The advanced study on the structure using common characterization techniques (TEM, MEB, XRD, Raman…) allows us to collect all the important information on their physical properties (magnetic, optical and electrical properties). In this thesis, we describe multiple ways to elaborate multifunctional nanostructures with 0D, 1D and 2D in order to study the parameters that control their chemical composition and structure. Besides, this research lead to the elaboration of new nanomaterials based on the oxide and the carbide forms of iron. Magnetic nanofibers with different morphologies (belts, tubes) were prepared using the electrospinning technique while controlling several experimental parameters : solution concentration, pyrolysis atmosphere, thermal treatment temperature… Moreover, thin layers doped with magnetic nanostructures were deposited on a pyrex substrate using the dip-coating technique. A full and detailed study on their structural properties was performed in order to reach the experimental parameters that allow us to obtain high quality products. Finally, we wish to explore the possible applications of these materials that present interesting electrical and magnetic characteristics.

Ces travaux de thèse ont eu deux objectifs: i) le développent de systèmes nanofluidique en utilisant une méthode non-lithographique, peu chère et facilement transposable à l'échelle industrielle ii) la compréhension des phénomènes nanofluidiques au travers des études expérimentales et de modélisation. Des couches minces mesoporeuses, en particulier des structures planaires avec des nanopiliers, ont été utilisé pour des études sur l'infiltration capillaire des liquides dans espaces confiné au niveau nanométrique. En plus des premiers tests pour des applications plus complexes comme des séparations et réactions nanoconfiné. Des structures mesoporeuses non-organisés ont aussi été étudiées pour déterminer la relation entre la nanostructure et la vitesse de remplissage capillaire. A été aussi démontré que pour des porosités avec des forts rétrécissements le remplissage capillaire se produit par l'intermédiaire d'une phase vapeur. Les échantillons ont été préparés par dip-coating. Une méthode de préparation basé sur une substitution de la plus grande parte de la solution à déposer par un fluide inerte a été développé. La méthode permet de réduire fortement le cout de procédé et, par conséquence, de faire des dépôts sur plus grande surface. Un effort dans la modélisation des phénomènes nanofluidiques a aussi été fait pendant cette thèse. Une méthode de simulation qui permet de décrire adéquatement les interactions hydrodynamiques dans un système nano a été utilisée pour simuler un flux électro-osmotique. La méthode, Stochastic Rotational Dynamics, a été valide par confrontation avec des résultats connus et l'influence des certains paramètres de simulation évaluée dans le détail. / This thesis had a dual purpose: i) the development of nanofluidic devices through not lithographic, cheap and scalable bottom-up approach ii) the understanding of nanofluidic phenomena both through experiments and simulations. Mesoporous thin films, in particular Pillared Planar Nanochannels (PPNs), were prepared and utilized to study the capillary infiltration of liquids in nanostructures and have been tested for future nanofluidic applications like separations and nanoconfined reactions. Non organized mesoporous films have also been studied to determine the relationship between nanostructure characteristics and infiltration speed. It has been also demonstrated that in the case of porosities with reduced bottle-necks capillary penetration is performed through a vapor mediated mechanism The samples were prepared by dip-coating. A novel method of preparation based on the substitution of a large part of the deposing solution in dip-coating with an inert fluid has been developed in order to strongly reduce the fabrication costs and allow the preparation of larger samples. Moreover advancement in control of the dip-coating technique in “acceleration-mode” to produce thickness gradients has been developed and some potential application linked to fluidics shown. Finally a part of the effort of this thesis has been placed in the modeling of the electro-osmotic phenomenon in nanostructures through a rather novel simulation method, Stochastic Rotational Dynamics, which takes into account the hydrodynamics and the other interactions inside a nanofluidic system. Validations of the method and further investigations in particular nanofluidic conditions have been performed.