In the present work, a new generation opaque polymer pigment with multihollow structure was synthesized by suspension polymerization of &ldquo / Water-in-Oil-in-Water&rdquo / (W/O/W) emulsion system. Oil phase was methyl methacrylate and ethylene glycol dimethacrylate monomer mixture at 1:1 weight ratio. The dimension and distribution of hollows inside polymer particles are dependent on the size of water droplets which are encapsulated in micelles. For Water-in-Oil (W/O) assembly, a hydrophobic surfactant and hydrophilic co-surfactant (Span 80-Tween 80) combination with a hydrophilic/lipophilic balance (HLB) value between 5-8 was used. The effects of surfactant and co-surfactant composition on the stability of the W/O emulsion and also on the size of water droplets were studied. In addition, the effect of the ultrasonication on the average size of water droplets was investigated. The hollow size distribution which may possibly give the maximum scattering efficiency was predicted by a mathematical model based on the Mie scattering. The optimum size distribution for W/O emulsion was obtained at the monomer/surfactant/water ratio of 75.5/9.4/15.1 after ultrasonication for 30 seconds at 80 W power. The W/O/W emulsion was prepared by dispersing the W/O emulsion in aqueous solution of hydrophilic Triton X-405. The influence of surfactant concentration and mechanical mixing on monomer droplets was investigated by size measurement and optical microscopy. After stabilizing with 1 %w/w polyvinylpyrrolidone (PVP) solution, the W/O/W emulsion was polymerized at 55 &deg / C for 20 h. The surface morphology of synthesized polymer pigments was analyzed by scanning electron microscopy (SEM) and the inner hollow structure was confirmed by transmission electron microscopy (TEM). The analysis indicated that multihollow opaque polymer pigments were successfully synthesized. The opacity, the L*a*b* color, and the gloss properties of polymer pigments were examined by spectrophotometer and glossmeter. The opacity values were assessed by contrast ratio measurements, and the synthesized polymer pigments provided up to 97.3 % opacity (50 %v/v solid content). In addition, the pigments exhibited low gloss values, and yielded matt films.

Ces travaux entrent dans la cadre du projet européen Fundamental and Applied Studies on Emulsion Stability (FASES). L'objectif de ce projet est de comprendre les phénomènes responsables de la déstabilisation des émulsions dans le temps, en relation avec les propriétés interfaciales de ces systèmes. Les travaux de thèse décrits dans ce mémoire se divisent en deux parties : ils portent tout d'abord sur la fabrication de gouttes d'émulsions eau-dans-huile par un procédé microfluidique, puis sur l'étude de la taille et de l'état de dispersion des gouttes sur la cristallisation de l'eau dispersée. Dans un premier temps, nous avons étudié les conditions opératoires permettant de fabriquer des gouttes de taille contrôlée par microfluidique avec le système de fluides mis en œuvre dans le projet FASES. Suivant le mode d'introduction des phases liquides, soit les débits, soit les pressions appliquées, ont été modifiés pour délimiter les zones de fabrication des gouttes. Afin de mieux comprendre les différences observées entre les deux modes d'introduction des fluides, un modèle reposant sur l'analogie entre circuits électriques et circuits microfluidiques a été proposé. Dans un second temps, les émulsions obtenues avec le dispositif microfluidique ont été analysées par calorimétrie et par thermo-microscopie. Les expériences ont permis de mettre en évidence, suivant les conditions étudiées (viscosité, taille des gouttes), différents processus de cristallisation des gouttes. Ces résultats mettent en avant directement le rôle du phénomène de sédimentation, les signaux de congélation observés dépendant fortement de l'état de dispersion des gouttes d'émulsion. / This thesis takes place in the framework of the European project FASES (Fundamentaland Applied Studies on Emulsion Stability). The aim of this project is to understand the phenomena responsible for emulsions destabilization, in relation with the interfacial properties of these systems. The research work described in this thesis is divided into twoparts : the first part deals with the creation of water-in-oil emulsion droplets in a microfluidic device, and in the second part, the influence of the size and the state of dispersion of the droplets on the crystallization of dispersed water is analyzed.To begin with, the operating conditions required to create emulsion droplets by microfluidic were studied. Two modes of introduction of the liquid phases, based on flow and pressure-driven techniques, were used to create the droplets. Maps of the droplet formation regions were drawn as a function of the applied flow rates and pressures. In order to compare the two processes, a model based on the analogy between electrical and microfluidic circuits was proposed.Then, emulsions obtained with the microfluidic device were analyzed by calorimetry and thermo-microscopy. The experimental results evidenced different droplet crystallization processes, depending on the system parameters (oil phase viscosity, droplet size …). The water freezing signals strongly depend on the state of dispersion of the droplets, showing themajor role of droplet sedimentation in the emulsion destabilization process.

Egg (the whole, the yolk or the white) is a natural product used since ancient times as tempera painting medium mainly in Europe and the Mediterranean Basin countries. In addition, egg is a complex multicomponent microstructured system susceptible of being influenced by the pigments that compose the paints, as well as a source of nutrient susceptible of biodeterioration. Modifying effect of artists' pigments on the binding medium as well as, the microbial biodeterioration are responsible for changes in the structure and composition of the binding medium and, consequently, on the physico-chemical properties of the paint. For this purpose, analytical techniques such as Fourier transform infrared spectroscopy - attenuated total reflection (FTIR-ATR) was used for the chemical characterization, Field emission scanning microscopy (FESEM) and Atomic force microscopy - nanoindentation (AFM-nanoindentation) were run for morphological and mechanical characterization of the deterioration processes resulted from the pigment-binder interactions involved in tempera painting. On the other hand, the current research report the application of the voltammetry of microparticles (VMP), complemented with FTIR-ATR, FESEM and AFM-nanoindentation techniques to monitor the deterioration of a series of tempera reconstructed model paint specimens under the action of different biological agents. This methodology would be of application for identifying the type of biological agent causing deterioration of painting, which is an important problem affecting cultural heritage. The analysis of biodeterioration processes is complicated by the fact that the action of microorganisms can affect both pigment and binding media. The deterioration of pictorial specimens by Acremonium chrysogenum, Aspergillus niger, Mucor rouxii, Penicillium chrysogenum and Trichoderma pseudokoningii fungi and Arthrobacter oxydans, Bacillus amyloliquefaciens and Streptomyces cellulofans bacteria was tested using sample-modified graphite electrodes immersed into aqueous electrolytes. Finally, the study carried out by means of FTIR-ATR, FESEM and AFM-nanoindentation confirms that egg proteins attached to the pigment grains changes their secondary structures. The results obtained also confirm that proteins and phospholipids are prevalently established linkages with the solid particles of pigment whereas triglycerides should be integrated in the complex binding network responsible for the cohesion of the paint film. Interactions between egg components with solid pigment particles are described and correlated with micromorphology and mechanical properties determined at micro- and nano-scale on the reconstructed model paint specimens. As a result of the crossing of VMP data with the results obtained by means of FTIR, FESEM and AFM-nanoindentation, the voltammetric signals obtained were associated to the electrochemical reduction of pigments and different complexes associated to the binding media. These results were particularly relevant in the study of biodeterioration, to allowing the electrochemical monitoring of biological attack. / El huevo (entero, yema o clara) es un producto natural utilizado desde la antigüedad como medio aglutinante en la pintura al temple, principalmente en Europa y los países de la cuenca mediterránea. Además, el huevo es un complejo sistema multicomponente microestructurado susceptible de ser alterado por los pigmentos que componen las pinturas, así como fuente de nutrientes susceptible de biodeterioro. El efecto de los pigmentos sobre el medio aglutinante, así como el biodeterioro microbiano son responsables de cambios en la estructura y composición del medio aglutinante y, por consiguiente, en las propiedades fisicoquímicas de la pintura. Es por esto que, se utilizaron técnicas analíticas como la Espectroscopía Infrarroja por Transformada de Fourier en modo Reflexión Total Atenuada (FTIR-ATR), para la caracterización química de los procesos de deterioro resultantes de las interacciones pigmento-aglutinante en la pintura al temple. Así mismo, se utilizó Microscopía Electrónica de Emisión de Barrido (FESEM) para el estudio morfológico de las muestras, y para el estudio de las propiedades mecánicas Microscopía de Fuerza Atómica en modo Nanoindentación (AFM-nanoindentación). Por otro lado, la presente investigación propone el uso de la Voltamperometría de Micropartículas (VMP), en conjunto con otras técnicas de análisis como FTIR-ATR, FESEM y AFM-nanoindentación para el estudio del biodeterioro producido por hongos y bacterias sobre una serie muestras pictóricas sometidas. El estudio de las alteraciones causadas por el biodeterioro es complicado por el hecho de que la acción de los microorganismos puede afectar tanto al pigmento como al medio aglutinante. Para esto, se prepararon una serie de muestras de pinturas al temple y emulsión que fueron inoculadas con los hongos Acremonium chrysogenum, Aspergillus niger, Mucor rouxii, Penicillium chrysogenum, y Trichoderma pseudokoningii, y las bacterias Arthrobacter oxydans, Bacillus amyloliquefaciens y Streptomyces cellulofans. El estudio voltamperometrico se realizó utilizando electrodos de grafito modificados con las muestras inmersos en un electrolito acuoso. Las conclusiones obtenidas de manera general, apuntan a que las proteínas presentes en el huevo cambian su estructura secundaria al adherirse a los granos de pigmento. La información química, morfológica y mecánica obtenida por las diferentes técnicas de análisis instrumental es consistente. Finalmente, como resultado del cruce de los datos VMP con los resultados obtenidos mediante FTIR, FESEM y AFM-nanoindentación, las señales voltamperometricas obtenidas se asociaron a la reducción electroquímica de los pigmentos y a los complejos formados con el medio aglutinante. Estos resultados fueron particularmente relevantes en el estudio del biodeterioro de las películas pictóricas inoculadas, para permitir la monitorización electroquímica del ataque microbiológico. / L'ou (sencer, rovell o clara) és un producte natural utilitzat des de l'antiguitat com a mitjà aglutinant en la pintura al tremp, principalment a Europa i els països de la conca mediterrània. A més, l'ou és un complex sistema multicomponent MICROESTRUCTURAT susceptible de ser alterat pels pigments que componen les pintures, així com a font de nutrients susceptible de biodeterioració. L'efecte dels pigments sobre el medi aglutinant, així com el BIODETERIORI microbià són responsables de canvis en l'estructura i composició del medi aglutinant i, per tant, en les propietats fisicoquímiques de la pintura. És per això que, es van utilitzar tècniques analítiques com l'Espectroscòpia Infraroja per Transformada de Fourier en mode Reflexió Total Atenuada (FTIR-ATR), per a la caracterització química dels processos de deteriorament resultants de les interaccions pigment-aglutinant en la pintura al tremp. Així mateix, es va utilitzar Microscòpia Electrònica d'emissió de Rastreig (FESEM) per a l'estudi morfològic de les mostres, i per a l'estudi de les propietats mecàniques Microscòpia de Força Atòmica en mode Nanoindentació (AFM-nanoindentació). D'altra banda, la present investigació proposa l'ús de la Voltamperometría de Micropartícules (VMP), en conjunt amb altres tècniques d'anàlisi, com FTIR-ATR, FESEM i AFM-nanoindentació per a l'estudi de l'biodeterioració produït per fongs i bacteris sobre una sèrie de mostres pictòriques sotmeses. L'estudi de les alteracions causades pel biodeteriori és complicat pel fet que l'acció dels microorganismes pot afectar tant el pigment com al medi aglutinant. Per això, es van preparar una sèrie de mostres de pintures al tremp i emulsió que van ser inoculades amb els fongs Acremonium chrysogenum, Aspergillus niger, Mucor rouxii, Penicillium chrysogenum, i Trichoderma pseudokoningii i els bacteris Arthrobacter oxydans, Bacillus amyloliquefaciens i Streptomyces cellulofans. L'estudi voltamperomètric es va realitzar utilitzant electrodes de grafit modificats amb les mostres immersos en un electròlit aquós. Les conclusions obtingudes de manera general, apunten que les proteïnes presents en l'ou canvien la seva estructura secundària al adherir-se als grans de pigment. La informació química, morfològica i mecànica obtinguda per les diferents tècniques d'anàlisi instrumental és consistent. Finalment, com a resultat de l'encreuament de les dades VMP amb els resultats obtinguts mitjançant FTIR, FESEM i AFM-nanoindentació, els senyals voltamperomètrics obtinguts es van associar a la reducció electroquímica dels pigments i als complexos formats amb el medi aglutinant. Aquests resultats van ser particularment rellevants en l'estudi del biodeteriori de les pel·lícules pictòriques inoculades, per tal de permetre la monitorització electroquímica de l'atac microbiològic. / Ortiz Miranda, A. (2017). Development of analytical methods for the characterization of tempera paintings at micro- and nano-scale and their deterioration and biodeterioration processes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90571 / TESIS

[pt] O aumento do fator de recuperação e o uso de métodos de recuperação avançada no atual cenário de novos patamares de preços representam um enorme desafio para a indústria do petróleo. Neste contexto, o uso de emulsões óleo-água como um método de recuperação avançada torna-se bastante atrativo. Diversos trabalhos mostraram um aumento no volume de óleo produzido através da injeção de emulsões óleo-água. Resultados de pesquisas experimentais indicam que a injeção de emulsões pode ser utilizada como agente de controle de mobilidade, bem como reduzindo a saturação residual de óleo. A aplicação do método de injeção alternada água-emulsão-água (WAE) requer o entendimento do escoamento de emulsões no meio poroso e dos mecanismos responsáveis pela melhora na recuperação. Este entendimento tanto na escala de poros como na escala de reservatórios permite incorporação destes mecanismos na modelagem para simulação de fluxo de reservatórios. No presente trabalho foi feita a incorporação dos efeitos gravitacionais no modelo desenvolvido para o escoamento de emulsões em meios porosos através da parametrização das curvas de permeabilidade relativa em função da concentração de gotas e do Número de Capilaridade. O processo WAE foi avaliado através de simulações em duas e três dimensões (2D/3D) utilizando um conjunto de camadas do segundo modelo comparativo do SPE10. Com simulações 2D e 3D foi possível realizar um estudo de sensibilidade do processo em relação ao momento da injeção de emulsão, o tamanho do banco, e as faixas de vazão e respectivos números de capilaridades de atuação da emulsão. / [en] In the current crude oil price scenario, the increase in oil recovery factor and the use of enhanced recovery methods represent a major challenge for the Oil Industry. In this context, the use of oil-water emulsion flooding as an enhanced recovery method becomes very attractive. Several studies have shown a significant potential to increase oil volume recovery by the injection of oil-water emulsions. Experimental results indicate that the emulsions injection can be used as a mobility control agent, resulting in a more uniform fluid displacement in the reservoir and lower residual oil saturation. Based on these experimental results, the most relevant parameters for emulsion injection performance effectiveness are droplet size, the local concentration of the dispersed phase of the emulsion and the local capillary number. The application of water alternating emulsion injection (WAE) method requires understanding of the flow of emulsions in porous media and the mechanisms responsible for the improved recovery. The understanding of this process in both porous scale and reservoir scale is fundamental to model emulsion injection effects in reservoir flow simulation. In this work, the gravitational effects was incorporated in the macroscopic model to represent flow of emulsions in porous media by relative permeability curves parametrization as function of emulsion concentration and of the local capillary number. The WAE process was evaluated in two and three dimensional simulations (2D / 3D) using a set of layers of the second SPE 10 comparative model. With 2D and 3D simulations, it was possible to explore a WAE injection performance sensitivity analysis considering the time at which the emulsion injection is started, the size of emulsion bank, and the injection flow rates and consequently the flow their capillary number.

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