Les procédés de séparation membranaires sont des techniques particulièrement adaptées aux exigences écologiques et industrielles en matière de traitement de l'eau. Parmi les différentes techniques de séparation existantes, la nanofiltration est un procédé économique permettant le dessalement et l'adoucissement de l'eau. En dépit du nombre croissant de travaux académiques ou industriels portant sur la nanofiltration ces dernières années, les phénomènes physiques impliqués dans le transport de solutés (en particuliers les sels) à travers les matériaux nanoporeux restent mal compris. En effet, les matériaux sont des membranes de polymère dont la structure est complexe et méconnue. Les propriétés des liquides en milieu confiné présentent de plus des propriétés inattendues. L'utilisation d'outils numériques permet d'explorer et d'améliorer la compréhension des mécanismes de transport à travers des membranes. Parmi les différentes approches existantes, les simulations de type dynamique moléculaire permettent de sonder les propriétés des liquides confinées à l'échelle moléculaire. L'objectif de cette thèse est d'analyser les propriétés de solutions aqueuses d'électrolytes confinées dans un nanopore modèle par simulation de dynamique moléculaire. Les systèmes étudiés sont constitués d'un pore de silice connecté à deux réservoirs contenant de l'eau salée. Deux types de simulations ont été réalisés. Au cours d'une simulation dite « à l'équilibre », les propriétés structurales, diélectriques et dynamiques des liquides ont été étudiées. Au cours des simulations ''hors-équilibre'', une différence de pression est appliquée entre les réservoirs afin de générer un écoulement. Les propriétés de transport de l'eau et des sels à travers le nanopore ont été étudiées. Ce travail s'inscrit dans le cadre du projet MUTINA financé par l'Agence Nationale de la Recherche (ANR 2011 BS09 002) portant sur la modélisation multi-échelle du transport d'ions en nanofiltration. / Membrane processes are very powerful techniques in term of water treatment. Nanofiltration is a recent membrane process mainly used for water desalination and water softening. Although nanofiltration has attracted increasing attention over the recent years, physical phenomenon related to species (especially aqueous salts) inside the membranes are still poorly understood at the nanoscale. The membranes used in a nanofiltration process (polymeric membranes) are indeed very complex and little is known about their structure. Moreover, liquids in a confined phase exhibit very different behaviour with respect from a bulk phase. In order to investigate the transport mechanisms, modelling tools are often used to reproduce the liquids and membranes behaviour. Molecular dynamic simulations are very useful in that case to gain insight into the liquid properties at the molecular scale. The aim of this thesis is to improve the understanding of the electrolytes transport inside a model nanopore. For this purpose, molecular simulations were carried out to simulate two kind of systems composed of pore connected to reservoirs filled of water and salts. On one hand, we performed equilibrium simulations to analyse the structural, dielectric and dynamic properties of confined liquids. On the other hand, non-equilibrium simulations were performed to generate a pressure-driven fluid flow to investigate water and ions transport. This work is part of the MUTINA project founded by the French National Research Agency for Research (ANR 2011 BS09 002) about multi-scale modelling of ion transport in nanofiltration.

Neste trabalho foi estudado o eletrólito sólido polimérico obtido através da plastificação do amido rico em amilopectina com glicerol em porcentagem de 30% em ralação a massa do amido utilizado, e contendo perclorato de litio (LiClO4), com uma razão [0]/[Li] = 10 (AGL). Com o objetivo de estudar a influência da umidade relativa nas propriedades de transporte iônico do eletrólito, foi utilizada a técnica de Ressonância Magnética Nuclear RMN. Neste trabalho, também, foram utilizadas outras técnicas de caracterização como: DSC, TGA e condutividade A.C. No estudo de RMN, foram realizadas medidas da forma de linha e da taxa de relaxação spin-rede do 1H e do 7Li em função da temperatura, a fim, de estudar a mobilidade do próton e do íon lítio no complexo polimérico. Os resultados desacoplamento do 7Li {1H} medidos na temperatura de 183K mostraram que 80% da largura de linha foi atribuída a interação heteronuclear Li-H. Os resultados da relaxação mostraram um aumento na mobilidade do complexo polimérico e do íon lítio com o aumento da hidratação do eletrólito. Os valores para a energia de ativação são da ordem de 0.20eV para o próton e 0.23eV para o lítio, consistente com os valores encontrados em outros eletrólitos sólidos poliméricos (0.2 - 0.3eV) / In this work we report the study of solid polymer electrolyte obtained from amylopectin rich starch plasticized with 30% in mass of glycerol and lithium perchlorate (LiClO4) with a reason [0]/[Li] = 10. With the objective to study the influence of the relative humidity in the properties of ionic transport of the electrolyte, the technique of Nuclear Magnetic Resonance - NMR was used. The samples were also characterized by DSC, TGA and A.C. conductivity. The mobility of protons and lithium ion were study through the temperature dependence of 1H and 7Li NMR lineshape and spin-lattice relaxation times. The 7Li {1H} decoupling results measured in the temperature of 183K, shows that 80% of the width of line was attributed to Li-H heteronuclear interaction. The relaxation results showed an increase of mobility of proton and lithium ion in the polymer complex with the increase of the relative humidity of the electrolyte. Activation energy of the arder of 0.20eV for the proton and 0.23eV for lithium were obtained from NMR measurements, consistent with the values found in other solid polymer electrolyte (0,2 - 0.3eV)

Esta tese apresenta os resultados de estudo de eletrólitos poliméricos obtidos a partir de agar com o propósito de serem aplicados em dispositivos eletrocrômicos (ECDs). Modificações físico-químicas foram efetuadas no agar através da adição do plastificante glicerol, bem como de formaldeído, além da adição de uma fonte de prótons, a partir de ácido acético, ou uma fonte de íons, utilizando-se LiClO4, para promover a condutividade iônica dos filmes. Foram também preparadas blendas a partir de agar com gelatina, com quitosana e com poli(etileno dióxido de tiofeno):poli(estireno) (PEDOT:PSS) com o objetivo de se obter novos materiais alternativos, para serem utilizados como eletrólitos poliméricos. O estudo revelou que todas as membranas apresentaram-se homogêneas, com estabilidade térmica até 200°C e com a estrutura predominantemente amorfa, com valores de temperatura vítrea em torno de -70 °C e transparência no visível de 90%. O manuseio das amostras obtidas revelou boa maleabilidade e aderência ao vidro. Os valores de condutividade iônica das membranas variaram entre 1x10-6 S/cm e 1,1x10-4 S/cm dependendo da composição e quantidade de ácido ou sal de lítio adicionado. No caso das amostras onde foi adicionado PEDOT:PSS, os resultados de condutividade obtidos foram na ordem de 10-4 S/cm, no entanto as amostras apresentaram a transparência somente de 17%. Foi feito um estudo preliminar, de aplicação dos melhores eletrólitos em ECDs revelando mudança de coloração entre o estado colorido e transparente de 25%, reversível inserção de carga entre 11 e 5,0 mC/cm2 e tempo de coloração de 15 segundos e de descoloração de 2 s. / With the aim to develop new electrochromic devices (ECDs), we present a study on polymer electrolytes obtained from agar. Agar was submitted to physicochemical modifications by adding glycerol as plasticizer and formaldehyde; besides, to promote ionic conductivity of the films, a proton source such as acetic acid, or an ion source, LiClO4, were also added. Moreover new alternative materials to be used as polymer electrolytes composed by blends of agar with gelatin, chitosan and poly (ethylene dioxide thiophene):poly(styrene sulfonate) (PEDOT:PSS) were also prepared and characterized. The study revealed that the membranes were homogeneous, with thermal stability up to 200°C and predominantly amorphous. The glass transition values were found to be around -70 °C and the transparency in the visible region of 90%. The ionic conductivity values were in the range of 1x10-6 S/cm to 1.1x10-4 S/cm, depending on composition and amount of added acid or salt. The ionic conductivity of the samples containing PEDOT:PSS were of the order of 10-4 S/cm, however, the corresponding transparencies were found to be about 17%, only. A preliminary study to qualify the performance of our best electrolytes in ECDs have shown a color change of 25%, reversible inserted charge of 5 to 11 mC/cm2 and coloring/bleaching times of 15 and 2 seconds, respectively.

This work deals with electrolytes and ionic liquids for Li-ion batteries. Following interaction of electrolytes and ionic liquids to electrodes material. In the theoretical part attention is focused on the description of battery electrolytes and ionic liquids for lithium-ion batteries.

This thesis deals with description of preparation and use of monomers and copolymers for gel polymer electrolytes usable in electrochemical power sources. This thesis is divided in theoretical and experimental part. The theoretical part describes electrolytes focused on gel polymer electrolytes, measuring methods and materials used for experiments. The experimental part deals with calculation of composition of polymer electrolytes, method of preparation and evaluation of measured results. The method of applying GPE to a negative LTO electrode and a positive NMC electrode is described too. Linear Sweep Voltammetry (LSV) and Potentiostatic Electrochemical Impedance Spectroscopy (PEIS), Cyclic Voltammetry (CV) and Galvanostatic Cycling with Potential Limitation (GCPL) were chosen for measurement of properties.

For centuries, researchers have attempted to devise the ideal parenteral nutritional product readily amenable to physiological requirements. Hyperalimentation, intravenous alimentation, parenteral alimentation, parenteral feeding, and total parenteral nutrition are synonyms which refer to a method of complete intravenous nutrition reserved for patients demonstrating negative nitrogen balance. The nutrient solution appeared to accommodate levels of potassium phosphate, calcium gluconate, and magnesium sulfate well in excess of “usual” therapeutic concentrations. Similarly, commonly employed vitamin supplements and insulin were examined in combination with the hyperalimentation solution and failed to demonstrate signs of physical incompatibility. However, instrumental analysis, i.e., U.V. spectroscopy and thin-layer chromatography, suggested, in fact, there may have been chemical interaction of Solu B Forte and MVI once admixed with the amino acids/dextrose solution. Yet, results of thin-layer chromatography did not appear to substantiate chemical interaction between MVI and the amino acids solution. The investigator contends further study of multiple vitamin infusion stability be completed before definite conclusions are formulated regarding their compatibility in this nutritional infusate.

This work deals with the preparation and measurement of an ionic conductivity of the gel polymer electrolytes prepared by various methods. In the theoretical part of the work, the types of conducting membranes, the development and the state of the art of the gel polymer electrolytes are summarized. The preparation and the results on ionic conductivity of the gels based on MMA, EMA and EOEMA are discussed in the experimental part.

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