Submitted by Fabiano Malheiro (fabianomalheiro22@hotmail.com) on 2019-02-01T12:26:25Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Revestimentos biomiméticos para superfícies de titânio em aplicações biomédicas.pdf: 8421154 bytes, checksum: 3579eb98998151e0dbd81f5e4fb61cec (MD5) / Made available in DSpace on 2019-02-01T12:26:25Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Revestimentos biomiméticos para superfícies de titânio em aplicações biomédicas.pdf: 8421154 bytes, checksum: 3579eb98998151e0dbd81f5e4fb61cec (MD5) Previous issue date: 2017-08-09 / Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul - FAPERGS / A osteointegração produto de próteses ósseas de titânio, continua sendo um ponto crítico e problemático recorrente no processo de reabilitação. Esforços para aperfeiçoar a resposta na interface "superfície-célula" dos implanto-materiais, têm sido direcionados para melhorar as propriedades físico-químicas das superfícies e induzir a adesão, proliferação, diferenciação ou apoptose celular. Revestimentos biomiméticos com superfícies sensíveis em titânio representam alternativas com resultados promissores para a resposta celular promovendo a formação de uma conexão funcional entre a superfície do material e o tecido ósseo. Para abordar esse tema foram realizados uma revisão sistemática relacionado ao tema e um estudo laboratorial para determinar as características de revestimentos de superfície biomiméticas (biomoléculas) em titânio e respostas celulares em relação à. No primeiro artigo foi realizada uma revisão sistemática para to avaliar a resposta celular produzida pelo tratamento de superfícies de titânio mediante o uso da técnica de polarização catódica.Treze estudos foram cumpriram com os critérios de inclusão e foram incluídos na revisão. Os resultados in vitro e in vivo relataram que o uso de polarização catódica promoveu superfícies com hidride e deposição efetiva e adesão das biomoléculas revestidas. O método eletroquímico, promoveu maior ou comparável viabilidade celular, proliferação, adesão, diferenciação ou crescimento ósseo. Para os artigos 2 e 3, foram desenvolvidos revestimentos de superfícies biomiméticas pelas técnicas de sol-gel dip-coating e polarização eletroquímica com diferentes configurações de superfícies estimulo responsivas multicamada e combinação de biomoléculas em titânio. O desenvolvimento das superfícies foi realizado e as amostras foram caracterizadas mediante microscopia de Força Atômica, Análise de Raios X de Energia Dispersa e citotoxicidade. A análise estatística foi descritiva e analítica (Stata 11.0). Os resultados foram submetidos a análise de variância ANOVA e/ou teste de Kruskall Wallis com nível de significância de 5% (p ≤ 0.05). No artigo 2, os resultados demonstraram que o grupo de superfícies modificadas com TiO2: Li+ (15%): Zr (15%)/PEG mediante o método sol-gel dip coating, promoveu maior crescimento celular (p>0,05) comparado ao resto dos grupos experimentais. No artigo 3, os resultados demonstraram que o grupo de superfícies modificadas com Indium tin oxide (In2O5Sn) mediante o método sol-gel dip coating, promoveu alto crescimento celular comparável estatisticamente ao grupo controle (p>0,05) e que o grupo que usou a técnica de polarização catódica promoveu crescimento celular. A polarização catódica promove alta viabilidade celular. In vitro, a técnica sol-gel e de polarização eletroquímica modificaram as superfícies de titânio. Entre as biomoléculas ativas, In2O5Sn e TiO2: Li+(15%):Zr(15%)/PEG aumentaram a viabilidade celular. / Osseointegration product of titanium bone prostheses continues to be a recurring and problematic point in the rehabilitation process. Efforts to improve the response in the interface "surface-cell" of implant-materials have been address to enhance physicochemical properties of the surfaces and induce cellular adhesion, proliferation, differentiation or apoptosis. Biomimetic coatings with titanium sensitive surfaces represent alternatives with promising results for the cellular response to osseointegration and can stimulate positive biological responses, promoting the formation of a functional connection between the surface of the material and the bone tissue, producing sufficient stimuli in the vascularization for the performance of tissue metabolic changes. To address this theme, a systematic review on the subject and a laboratory study were carried out to determine the characteristics of titanium biomimetic surface coatings (biomolecules) and the cellular responses. In the first article, a systematic review was carried out to evaluate the cellular response produced by the treatment of titanium surfaces using the cathodic polarization technique. Thirteen studies accomplished the inclusion criteria and were included in the review. In vitro and in vivo results reported that the use of cathodic polarization promoted surfaces with hydride and effective deposition and adhesion of the coated biomolecules. The electrochemical method promoted higher or comparable cellular viability, proliferation, adhesion, differentiation or bone growth than the group’s control. For articles 2 and 3, biomimetic surface coatings were developed by integrated dipcoating sol-gel techniques and electrochemical polarization with different configurations of multilayer responsive stimulus surfaces and combination of biomolecules in titanium. Surface development was performed and Atomic Force Microscopy, Dispersed Energy X-ray Analysis and cytotoxicity, characterized the samples. The statistical analysis was descriptive and analytical (Stata 11.0). The results were submitted to the analysis of variance ANOVA and/or Kruskal Wallis test to determine possible differences between the groups with a significance level of 5% (p ≤ 0.05). In article 2, the results showed that the group of modified surfaces with TiO2: Li + (15%): Zr (15%)/ PEG by the sol-gel dipcoating method, promoted higher cell growth (p> 0.05) than the rest of the experimental groups. In article 3, the results showed that the group of surfaces modified with Indium tin oxide (In2O5Sn) by the solgel dip coating method promoted high cell growth statistically comparable to the control group (p> 0.05) and the group that used the cathodic polarization technique promoted cell growth. Cathodic polarization promotes high cell viability and bone growth. In vitro, the sol-gel dip coating technique and electrochemical polarization modified titanium surfaces. Among the active biomolecules, In2O5Sn and TiO2: Li+ (15%): Zr (15%) / PEG increased cell viability.

No description available.

Nous étudions la structuration de dépôts lors du séchage de suspensions colloïdales et de solutions polymères, dans une cellule de Hele-Shaw verticale immergée dans un réservoir (même principe qu'une expérience de dip-coating). La vitesse de la ligne de contact est contrôlée en pompant la solution du réservoir. A faible nombre capillaire un phénomène d'accrochage-décrochage de la ligne triple apparaît lors du séchage des suspensions colloïdales de silice. Nous étudions la longueur d'onde et la morphologie du dépôt en fonction de la vitesse moyenne de la ligne de contact. La variation de force d'accrochage est déduite de l'observation en ligne du mouvement de la ligne de contact. Nous étudions l'influence du pH de la solution et de la taille des particules sur le dépôt. Dans les mêmes conditions, les films obtenus pas séchage de solutions polymères sont presque plats. On observe cependant une structuration à plus haute température. Dans la seconde partie du manuscrit, un modèle 2D a été développé pour décrire l'écoulement dans la cellule de Hele-Shaw induit par la vitesse imposée et le flux d'évaporation non uniforme. Les équations de Stokes et la loi de Fick sont utilisées pour décrire l'écoulement et les transferts. Une troncature est appliquée à la pointe du ménisque pour s'affranchir de la singularité due à la divergence du flux d'évaporation. L'approximation de lubrification et les bilans de masse permettent de définir les conditions aux limites à la troncature. L'épaisseur du dépôt et les propriétés de l'écoulement sont étudiées en fonction des paramètres du processus (vitesse imposée, flux d'évaporation, concentration) ainsi que des propriétés du système

Este trabalho investigou a obtenção de filmes de TiO2 por sol-gel e dipcoating (SGDC) e sua caracterização microestrutural e como fotocatalisador para a produção de hidrogênio a partir da água. Os precursores e reagentes utilizados foram: propóxido de titânio, ácido acético, etanol anidro, acetilacetona, Triton X-100 e polivinilbutiral (PVB). Foram preparadas 2 soluções precursoras, uma com PVB e outra sem. Foram produzidos filmes com 1, 2 e 3 camadas através da técnica de dip-coating. Os filmes foram tratados termicamente a 400, 500 e 600ºC, com uma taxa de 100ºC/h e um patamar de 2 h. O TiO2 sintetizado e os filmes produzidos foram caracterizados por difração de raios X (DRX) quanto à cristalinidade, fases presentes e tamanho de cristalito; microscopia eletrônica de varredura (MEV), adsorção de nitrogênio (método BET), análises termogravimétricas (ATG) e termodiferenciais (ATD), elipsometria espectroscópica, perfilometria óptica, espectroscopia Raman e de reflectância difusa (determinação do band gap). Após o tratamento térmico os filmes apresentaram uma microestrutura bastante irregular e com muitas trincas, com a presença da fase anatase em todas as temperaturas de tratamento térmico, e um teor de 3,7% de rutilo à 600ºC. O band gap dos filmes aumentou com a quantidade de camadas adicionadas, com a elevação da temperatura de tratamento térmico e adição de PVB. As medidas de fotocorrente foram realizadas no escuro e sob iluminação de lâmpada de Xe com 250W (simulador de luz solar de 1,5AM). A maior fotocorrente medida foi de 12 μA a 0,5V. A produção de H2 aumentou linearmente com o tempo de exposição para ambas as amostras com PVB. Foi possível relacionar a adição do PVB com o favorecimento da fotoatividade dos filmes de TiO2. / This work has investigated the effect of polyvinyl butyral addition in the synthesis of TiO2 films by sol-gel and dip-coating, their microstructural features and their photoelectrochemical activity for water-splitting hydrogen production. The precursors and reagents used were: titanium propoxide, acetic acid, anhydrous ethanol, acetylacetone, Triton X-100 and polyvinyl butyral (PVB). Two precursor solutions were prepared: one with PVB and another without it. The dip-coating technique was used to produce films with 1, 2 and 3 layers. The films were heat treated at 400, 500 and 600ºC, at a rate of 100°C/h and dwelling time of 2h. Afterwards the synthesized films were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM), nitrogen adsorption (BET method), thermogravimetric (TGA) and differential thermal analysis (DTA), spectroscopic ellipsometry, optical profilometry, Raman and diffuse reflectance spectroscopy (determination of the band gap). The films after heat treatment showed a very irregular microstructure with many cracks. The anatase phase was presented in all temperatures and a small content of rutile at 600 °C (around 3.7%) was identified. The band gap of the films increased with the number of layers, heat treatment and addition of PVB. The photocurrent measurements were carried out in the dark and under illumination with 250W Xe, using a sunlight simulator (1,5AM). The highest photocurrent was 12A at 0.5V. The H2 production increased linearly with time of exposure for both samples with PVB. Therefore, it was possible to relate the addition of PVB with improvement the photoactivity of TiO2 films.

Este trabalho investigou a obtenção de filmes de TiO2 por sol-gel e dipcoating (SGDC) e sua caracterização microestrutural e como fotocatalisador para a produção de hidrogênio a partir da água. Os precursores e reagentes utilizados foram: propóxido de titânio, ácido acético, etanol anidro, acetilacetona, Triton X-100 e polivinilbutiral (PVB). Foram preparadas 2 soluções precursoras, uma com PVB e outra sem. Foram produzidos filmes com 1, 2 e 3 camadas através da técnica de dip-coating. Os filmes foram tratados termicamente a 400, 500 e 600ºC, com uma taxa de 100ºC/h e um patamar de 2 h. O TiO2 sintetizado e os filmes produzidos foram caracterizados por difração de raios X (DRX) quanto à cristalinidade, fases presentes e tamanho de cristalito; microscopia eletrônica de varredura (MEV), adsorção de nitrogênio (método BET), análises termogravimétricas (ATG) e termodiferenciais (ATD), elipsometria espectroscópica, perfilometria óptica, espectroscopia Raman e de reflectância difusa (determinação do band gap). Após o tratamento térmico os filmes apresentaram uma microestrutura bastante irregular e com muitas trincas, com a presença da fase anatase em todas as temperaturas de tratamento térmico, e um teor de 3,7% de rutilo à 600ºC. O band gap dos filmes aumentou com a quantidade de camadas adicionadas, com a elevação da temperatura de tratamento térmico e adição de PVB. As medidas de fotocorrente foram realizadas no escuro e sob iluminação de lâmpada de Xe com 250W (simulador de luz solar de 1,5AM). A maior fotocorrente medida foi de 12 μA a 0,5V. A produção de H2 aumentou linearmente com o tempo de exposição para ambas as amostras com PVB. Foi possível relacionar a adição do PVB com o favorecimento da fotoatividade dos filmes de TiO2. / This work has investigated the effect of polyvinyl butyral addition in the synthesis of TiO2 films by sol-gel and dip-coating, their microstructural features and their photoelectrochemical activity for water-splitting hydrogen production. The precursors and reagents used were: titanium propoxide, acetic acid, anhydrous ethanol, acetylacetone, Triton X-100 and polyvinyl butyral (PVB). Two precursor solutions were prepared: one with PVB and another without it. The dip-coating technique was used to produce films with 1, 2 and 3 layers. The films were heat treated at 400, 500 and 600ºC, at a rate of 100°C/h and dwelling time of 2h. Afterwards the synthesized films were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM), nitrogen adsorption (BET method), thermogravimetric (TGA) and differential thermal analysis (DTA), spectroscopic ellipsometry, optical profilometry, Raman and diffuse reflectance spectroscopy (determination of the band gap). The films after heat treatment showed a very irregular microstructure with many cracks. The anatase phase was presented in all temperatures and a small content of rutile at 600 °C (around 3.7%) was identified. The band gap of the films increased with the number of layers, heat treatment and addition of PVB. The photocurrent measurements were carried out in the dark and under illumination with 250W Xe, using a sunlight simulator (1,5AM). The highest photocurrent was 12A at 0.5V. The H2 production increased linearly with time of exposure for both samples with PVB. Therefore, it was possible to relate the addition of PVB with improvement the photoactivity of TiO2 films.

Este trabalho investigou a obtenção de filmes de TiO2 por sol-gel e dipcoating (SGDC) e sua caracterização microestrutural e como fotocatalisador para a produção de hidrogênio a partir da água. Os precursores e reagentes utilizados foram: propóxido de titânio, ácido acético, etanol anidro, acetilacetona, Triton X-100 e polivinilbutiral (PVB). Foram preparadas 2 soluções precursoras, uma com PVB e outra sem. Foram produzidos filmes com 1, 2 e 3 camadas através da técnica de dip-coating. Os filmes foram tratados termicamente a 400, 500 e 600ºC, com uma taxa de 100ºC/h e um patamar de 2 h. O TiO2 sintetizado e os filmes produzidos foram caracterizados por difração de raios X (DRX) quanto à cristalinidade, fases presentes e tamanho de cristalito; microscopia eletrônica de varredura (MEV), adsorção de nitrogênio (método BET), análises termogravimétricas (ATG) e termodiferenciais (ATD), elipsometria espectroscópica, perfilometria óptica, espectroscopia Raman e de reflectância difusa (determinação do band gap). Após o tratamento térmico os filmes apresentaram uma microestrutura bastante irregular e com muitas trincas, com a presença da fase anatase em todas as temperaturas de tratamento térmico, e um teor de 3,7% de rutilo à 600ºC. O band gap dos filmes aumentou com a quantidade de camadas adicionadas, com a elevação da temperatura de tratamento térmico e adição de PVB. As medidas de fotocorrente foram realizadas no escuro e sob iluminação de lâmpada de Xe com 250W (simulador de luz solar de 1,5AM). A maior fotocorrente medida foi de 12 μA a 0,5V. A produção de H2 aumentou linearmente com o tempo de exposição para ambas as amostras com PVB. Foi possível relacionar a adição do PVB com o favorecimento da fotoatividade dos filmes de TiO2. / This work has investigated the effect of polyvinyl butyral addition in the synthesis of TiO2 films by sol-gel and dip-coating, their microstructural features and their photoelectrochemical activity for water-splitting hydrogen production. The precursors and reagents used were: titanium propoxide, acetic acid, anhydrous ethanol, acetylacetone, Triton X-100 and polyvinyl butyral (PVB). Two precursor solutions were prepared: one with PVB and another without it. The dip-coating technique was used to produce films with 1, 2 and 3 layers. The films were heat treated at 400, 500 and 600ºC, at a rate of 100°C/h and dwelling time of 2h. Afterwards the synthesized films were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM), nitrogen adsorption (BET method), thermogravimetric (TGA) and differential thermal analysis (DTA), spectroscopic ellipsometry, optical profilometry, Raman and diffuse reflectance spectroscopy (determination of the band gap). The films after heat treatment showed a very irregular microstructure with many cracks. The anatase phase was presented in all temperatures and a small content of rutile at 600 °C (around 3.7%) was identified. The band gap of the films increased with the number of layers, heat treatment and addition of PVB. The photocurrent measurements were carried out in the dark and under illumination with 250W Xe, using a sunlight simulator (1,5AM). The highest photocurrent was 12A at 0.5V. The H2 production increased linearly with time of exposure for both samples with PVB. Therefore, it was possible to relate the addition of PVB with improvement the photoactivity of TiO2 films.

Les fluides à seuil sont des matériaux utilisés dans de nombreux procédés industriels au cours desquels ils sont mis en écoulement via leur interaction avec des outils solides. Afin de mieux comprendre comment ils s'étalent sur des surfaces, nous avons étudié d'une part leur enduction verticale sur une plaque mince et d'autre part leur étalement horizontal à l'aide d'une lame. Ces deux études se sont appuyées sur des mesures macroscopiques permettant de suivre la force appliquée à l'outil et des mesures microscopiques de PIV pour déterminer les champs de vitesse dans le matériau. Après confirmation de leur validité par comparaison avec nos résultats expérimentaux, des simulations numériques basées sur la programmation conique ont permis de préciser les écoulements en jeu. Pour l'enduction par trempage, nous observons que dans notre gamme d'étude, le dépôt de fluide à seuil sur la plaque est millimétrique et d'épaisseur constante, sauf aux extrémités. Selon le rapport des forces visqueuses et plastiques, l'enduction est régie par un équilibre "seuillo-gravitaire" ou "visco-gravitaire". Nous avons ensuite caractérisé l'écoulement généré dans le bain par le déplacement de la plaque afin d'expliciter l'origine du phénomène d'enduction. Les simulations numériques précisent la forme de cet écoulement. L'étalement horizontal dans un canal à l'aide d'une lame mince conduit au déplacement d'un amas de fluide faiblement cisaillé par rapport à une région de fluide au repos, par l'intermédiaire d'une couche cisaillée. Nous montrons qu'un modèle simple permet de prédire la dynamique de croissance de l'amas et la relie à la force normale à la lame / Yield stress fluids are used in various industrial processes in which solid tools make them flow. To have a better understanding on how they spread on surfaces, we first studied the vertical coating on a thin plate and then the horizontal blade-coating. Both studies are based on macroscopic measures recording the force applied on the plate and on the microscopic determination on the velocity fields in the fluid by PIV. Numerical simulations based on cone programming, which validity had been confirmed in comparison to our experimental results, specified the flows at stake. In dip-coating, we observed than within our framework, the yield stress fluid deposit on the plate is millimetric and of constant thickness, except on the tips. According to the value of the viscous over plastic forces ratio, the coating is led by a "yield-gravity" or a "visco-gravity" balance. Then, we characterized the flow generated in the bath by the plate displacement in order to clarify the origin of the coating phenomenon. The numerical simulations specified the flow characteristics. The horizontal blade-coating in a channel involves the displacement of a weakly sheared cluster of fluid in relation to a part of fluid at rest, through a sheared layer. We showed that the growing dynamic of the cluster is described with a simple model which links it to the normal force to the plate

L’objectif de ce travail a été d’étudier des matériaux semiconducteurs de type p comme photocathode pour la réduction de protons dans le cadre de la photoélectrolyse de l’eau. Ainsi, deux types de matériaux ont été étudiés, des oxydes de cuivre, Cu2O et CuO, et des matériaux à structure pérovskite (ATiO3, A=Ca, Ba, Sr) dopées au fer et à l’azote. Les oxydes de cuivre ont été synthétisés par deux voies différentes afin d’obtenir des films : par voie sol-gel couplée au dip-coating et par électro-dépôt et anodisation du cuivre. La photocorrosion des oxydes de cuivre en milieu aqueux et sous illumination a été mise en évidence. La protection des oxydes de cuivre via une hétérojonction avec un semiconducteur de type n (TiO2 ou BaTiO3) a révélé une meilleure stabilité des électrodes au cours du temps ainsi que des photocourants élevés grâce à une composition et une architecture originales. Les pérovskites ont été synthétisées par voie sol-gel couplée au dip-coating. Ce sont des semiconducteurs de type n ; ainsi l’étude du dopage au fer, pour substituer le titane, et à l’azote, pour substituer l’oxygène, a mis en évidence un changement de nature de type n à type p, ainsi qu’une diminution de la largeur de bande interdite. Les propriétés physico-chimiques de toutes les électrodes synthétisées ont été caractérisées (structure cristalline, morphologie, propriétés optiques et électrochimiques) et discutées en fonction de leur composition et des paramètres de synthèse. Ces travaux ont permis d’élaborer des photocathodes originales, performantes et stables au cours du temps (oxydes de cuivre protégées), et de démontrer l’utilisation de pérovskites dopées pour cette application. / The aim of this work was to study p-type semiconducting materials as photocathodes for protons reduction into H2 for water splitting application. Two types of materials have been studied: copper oxides, Cu2O and CuO, and materials with a perovskite structure (ATiO3, A=Ca, Ba, Sr) doped by iron and nitrogen. Copper oxides have been synthetized by two different ways in order to obtain films: sol-gel process coupled with dip-coating and copper plating and anodization. Copper oxides photocorrosion has been highlighted in aqueous environment and under illumination. Their protection via a heterojunction with an n-type semiconductor (TiO2 and BaTiO3) improved electrodes stability over time and photocurrents, thanks to original composition and architecture. Perovskites have been synthetized by sol-gel process coupled with dip-coating. They are well-known as n-type semiconductors; so the study of doping with iron, to substitute titanium, and with nitrogen, to substitute oxygen, shows a change from n-type to p-type, and a reduction of the band gap. The physical and chemical properties of the synthetized electrodes were characterized (crystal structure, morphology, optical and photoelectrochemical properties) and discussed according to the composition and synthesis parameters. This work enables to obtain original, efficient, and stable over time, photocathodes (protected copper oxides) and to demonstrate the potential use of doped perovskites for this application.

[ES] En la presente tesis se han desarrollados estudios sobre reactores de membrana de alta temperatura. Entre estos se puede diferenciar entre un trabajo experimental y un trabajo de simulación. En el bloque experimental se han desarrollado electrodos basados en cobre para reactores de membrana electroquímicos tubulares de alta temperatura basados en electrolitos protónicos. Para depositar estos electrodos sobre los tubos se han desarrollado diferentes técnicas. Se ha optimizado el método dip-coating para depositar un cermet basado en cobre utilizando la misma cerámica que el electrolito de los soportes tubulares. Las condiciones con las que se llevó a cabo el proceso de dip-coating provocan disminuciones de varios ordenes de magnitud en la resistencia de polarización del electrodo final. Se trata de un método que es muy sensible a posibles defectos en electrolito, como pequeñas grietas o poros, ya que el cobre del electrodo depositado se introduce por estos defectos reaccionando con el níquel del electrodo interno. Asimismo, se ha empleado el método de sputtering para depositar cobre metálico sobre soportes tubulares electroquímicos. Aumentar la temperatura de deposición genera mejores fijaciones electrodo-electrolito. Las celdas con el cobre depositado a alta temperatura mostraron resistencias de polarización inferiores a 0.1 ¿·cm^2. En el bloque de simulaciones mediante métodos de elementos finitos se han desarrollado diferentes modelos para la caracterización de los fenómenos que tienen lugar en reactores de membrana de alta temperatura. Se ha estudiado: (i) la permeación de oxígeno a través de una membrana de conducción iónica-electrónica mixta; (ii) la electrólisis del agua utilizando celdas basadas en conductores protónicos de alta temperatura; (iii) la integración de una celda protónica para la extracción de hidrógeno en un reformador de metano; (iv) la integración de una celda de conductividad co-iónica en la deshidroaromatización de metano en un reactor de lecho catalítico. El modelo de permeación de oxígeno a través de una membrana de conductividad mixta se ajustó a datos experimentales. El modelo ajustado ha permitido caracterizar la importancia del efecto dilutivo y de arrastre sobre el transporte de oxígeno a través de la membrana. Se ha observado que, aunque el efecto de arrastre tenga menor importancia que el dilutivo, su efecto es importante ya que previene la formación de concentraciones de polarización. El estudio de electrolizadores que utilizan conductores protónicos sólidos de alta temperatura ha permitido estudiar el efecto del escalado en este proceso y evaluar la eficiencia en el almacenamiento de energía. El modelo de un reactor de membrana electroquímico basado en conductores protónicos integrado en un reformador de metano ha permitido comprobar que la demanda térmica del proceso se cubre por el efecto Joule y la electrocompresión del hidrógeno. Se ha comprobado como el coarsening observado en las partículas de níquel no limita la extracción de hidrógeno para la celda estudiada. Un último modelo fue construido para estudiar un reactor de membrana para el proceso de deshidrogenación de metano utilizando una celda co-iónica. El modelo fue validado utilizando datos experimentales. Se utilizó el modelo validado para realizar estudios para analizar posibles limitaciones del proceso. Finalmente, se ha comprobado que el desplazamiento del equilibrio de reacción mediante la extracción de hidrógeno se frena debido a limitaciones cinéticas. / [CA] Esta tesi presenta resultats sobre reactors de membrana a alta temperatura. Dos blocs diferenciades poden ser identificats: (i) treball experimental; (ii) treball de modelat. En el bloc experimental, elèctrodes basats en coure han siguts optimitzats per a tubular cells de conductor protòniques. La deposició de la capa basada en coure es va fer amb diferents tècniques. La tècnica de dip-coating ha sigut usada per a depositar una capa de cermet basada en coure. Aquesta tècnica es molt sensible a les condicions amb les que es desenvolupa la deposició perquè causa canvis de varis ordres de magnitud en la resistència de polarització del elèctrode. A més, la tècnica de sputtering ha sigut triada per a depositar coure. Per a depositar correctament la capa de coure, altes temperatures durant la deposició foren requerides. El elèctrode optimitzat presenta resistències de polarització inferiors a 0.1 ¿·cm2. En el treball de modelat, la metodologia de elements finits va ser utilitzada per a modelar diferents fenòmens concernits a reactors de membrana de elevada temperatura. La permeació de oxigen per membranes de conducció mixta ha sigut modelada per a avaluar la importància de la dilució i del arrossegament. Els resultats mostren que, encara que el efecte dilutiu es predominant, el efecte del arrossegament no pot ser depreciat. Un adequat arrossegament del oxigen permeat es necessari per evitar polaritzacions en la concentració del oxigen els quals limitarien la permeació. El efecte del arrossegament es major quan el gas portador es mes pesat. El model per estudiar un procés de electròlisis basat en conductors protòniques a elevada temperatura ha permès estudiar l'efecte de l'escalat de aquest procés i avaluar l'eficiència en l'emmagatzemament d'energia. Modelant un reformador de membrana protònica ha permès comprovar la microintegració tèrmica de tots el fenòmens que tenen lloc en aquest procés. Aquest procés compren les reaccions de reformat, extracció electroquímica de hidrogen i electrocompressió del hidrogen generat. La electrocompressió del hidrogen és un procés isoterma que allibera la energia demanda en forma de calor. El model ha permès comprovar que l'engrossiment de les partícules de níquel no limita l'extracció de hidrogen. Un últim model va ser construït per estudiar l'extracció de hidrogen en un reactor de membrana per al procés de dehidroaromatizatió de metà. El reactor de membrana utilitza materials co-iòniques per l'extracció de hidrogen de la càmera de reacció. Aquest model va ser validat amb resultats experimentals. El model va mostrar que no hi ha limitacions amb la difusió del hidrogen. A més, el desplaçament del equilibri mediant l'extracció de hidrogen està limitat per la baixa activitat cinètica del procés. / [EN] In this thesis several studies were developed about membranes reactor at high temperature. Two differentiated blocks could be identified: (i) experimental works; (ii) modelling works. In the experimental block, electrodes based on copper was developed for tubular protonic based cells. The deposition of the copper layer on the tubes was developed by different techniques. Dip-coating method was optimized to a copper-based cermet on the tube. Conditions of the dip-coating procedure has a critical impact in the final performance of the electrochemical cell whose supposes several orders of magnitude in the polarization resistance. It is a sensitive process with the defect of the tube as shows the copper spread over these defects. Additionally, sputtering technique was used to deposit copper layer on the tube. High temperature is required to achieve suitable attachments copper-tube. This high temperature deposited layer present polarization resistances lower than 0.1 ¿·cm2. In the modelling block, finite element methodology was used to build different models to study different phenomena concerning membrane reactors at high temperature. It was studied: (i) the oxygen permeation across a mixed ionic and electronic conducting membrane; (ii) water electrolysis based on high temperature protonic cells; (iii) hydrogen extraction from a steam methane reforming using a protonic cell; (iv) the intensification of the methane dehydromatization reactor using co-ionic membrane. Oxygen permeation model was built to evaluate the effect of the dilutive and the sweep contribution over the permeation process. The fitted model allowed the importance of the dilutive and sweep effect over the oxygen permeation. Although the sweep effect present lower influence in the oxygen transport across the membrane, its effect prevents concentration polarization limitations. Modelling the protonic cell based electrolysis allowed to study the effect of the scale up in this process and to evaluate the efficiency in the energy storing in form of hydrogen. Modelling protonic membrane reformer allowed checking the thermal microintegration of all the heats which take place in the setup. The electrocompression of hydrogen is an isothermal phenomenon which releases the demanded energy as heat. The model allowed to check the coarsening of the Ni particles does not limit the hydrogen extraction for the studied cell. A final model was built to study a catalytic membrane reactor for the methane dehydroaromatization using co-ionic conducting cells. The model was validated using experimental data. Additionally, different studies were performed to analyze possible limitation in the process. Results show that there are no hydrogen diffusion limitations in this process. Additionally, the shift of the equilibrium by extracting hydrogen has to be stopped because kinetic limitations. / Catalán Martínez, D. (2019). Development of electrocatalytic layers and thermo-fluid dynamic evaluation for high temperature membrane reactors [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/135278

L'étude du transport électronique dans des nano-objets métalliques et magnétiques issus de la chimie est un challenge en spintronique. En particulier, le manque de résultats expérimentaux révèle la difficulté à positionner ces nano-objets entre des électrodes de mesures tout en préservant leurs propriétés (magnétisme, intégrité des barrières tunnel organiques...). Ce travail de thèse vise à contourner ces difficultés et à étudier le magnétotransport dans ces systèmes. Pour cela, nous avons conçu et développé à l'intérieur d'une boîte à gants couplée à un bâti de pulvérisation cathodique des systèmes expérimentaux d'assemblages de nano-objets. Nous avons étudié les mécanismes mis en jeu lors de l'assemblage par la technique de dip coating, et réussi à déposer des monocouches de nanoparticules (NPs) de natures différentes (FeCo, Fe, Co) sur des surfaces d'Au, de SiO2 et de résine fine (40 nm). Ces résultats, couplés à une technique de nanoindentation, ont permis de mesurer quelques - voire une- NP(s). Une autre technique, la diélectrophorèse, s'est révélée simple et efficace pour piéger et orienter des nano-objets de taille, de nature, et de forme différentes entre des électrodes. Grâce à cette technique et au dépôt d'une couche protectrice d'alumine, nous avons étudié les propriétés de magnétotransport de plusieurs types de nano-objets sensibles à l'oxydation ou à la vapeur d'eau: NPs de Fe, de Co, FeCo et [Fe(H-trz)2(trz)](BF4)] (composés à transition de spin). Trois jeux de barrières tunnel organiques greffés sur des NPs de fer ont présenté de la magnétorésistance tunnel jusqu'à température ambiante. De plus, des nano-objets de [Fe(H-trz)2(trz)](BF4)] de facteurs de forme variable, ont montré une variation de la conductance liée à la transition de spin. Enfin, nous avons étudié l'influence de la longueur des ligands sur les propriétés de conductions de NPs de Cobalt, qui a validé nos méthodes d'échange de ligands et ont pu être analysées quantitativement. Nos travaux rendent désormais envisageable l'utilisation de NPs issues de la chimie dans différents domaines de la spintronique.