No description available.

Solid-state batteries are gaining a lot of attention in the commecial sector today. Development of the solid state electrolytes is an important part in making commercially viable solid-state batteries. While many solid-state electrolytes are struggling with low ionic conductivity, some have shown comparatively high conductivities that can be engineered to perform better to be implemented for consumer market. Silica based solid composite electrolytes (SCEs) are one of the materials that are of huge interest as solid-state electrolytes. As a continuation of the previous research into the silica based SCE’s, the current work focuses on the study of SCEs based on the commercially available mesoporous silica (MPS) of different pore sizes and nanosized silica powder (SNP). Ionic Liquid electrolyte (ILE) based on Li-TFSI and BMP-TFSI mixture was used to prepare composities under different humidity conditions. The effect of the extent of -OH group functionalization of silica, determined by FTIR on treated and untreated powders, on ionic conductivity was also evaluated. Obtained composities were evaluated with electrochemical impedance spectroscopy (EIS) and analysed with TGA to establish correlations based on particle size and pore characteristics of MPS powder. Camparison with SNP was also made in anticipation to draw correlations with MPS. It was found that the pore size and pore volume change have more impact on the conductivity compared to surafce area of commercially obtained MPS and an unexplored pheonomenon was observed in case of SNP based SCE’s. Glovebox (GB) samples at relative humidity (RH)-0.005% have higher conductivity than dryroom samples at RH-0.5%. These findings can be used for a future reference in evaluating commercial MPS based composites as solid-state electrolytes. / Solid-state-batterier får stor uppmärksamhet i den kommersiella sektorn idag. Utveckling av fasta elektrolyter är en viktig del för att göra kommersiellt gångbara solid state-batterier. Medan många fasta elektrolyter kämpar med låg jonledningsförmåga, har vissa visat jämförelsevis höga ledningsförmåga som kan konstrueras för att prestera bättre för att implementeras för konsumentmarknaden. Kiselbaserade fasta kompositelektrolyter (SCE) är ett av de material som är av stort intresse som fasta elektrolyter. Som en fortsättning på den tidigare forskningen om de kiselbaserade SCE:erna fokuserar det nuvarande arbetet på studiet av SCE:er baserade på den kommersiellt tillgängliga mesoporösa kiseldioxiden (MPS) av olika porstorlekar och nanosized kiseldioxidpulver (SNP). Jonisk flytande elektrolyt (ILE) baserad på Li-TFSI och BMP-TFSI-blandning användes för att framställa kompositer under olika luftfuktighetsförhållanden. Effekten av omfattningen av -OH-gruppfunktionalisering av kiseldioxid, bestämd med FTIR på behandlade och obehandlade pulver, på jonkonduktiviteten utvärderades också. Erhållna sammansättningar utvärderades med elektrokemisk impedansspektroskopi (EIS) och analyserades med TGA för att fastställa korrelationer baserat på partikelstorlek och poregenskaper hos MPS-pulver. Kamparison med SNP gjordes också i väntan på att dra korrelationer med MPS. Det visade sig att porstorleken och porvolymsförändringen har mer inverkan på konduktiviteten jämfört med ytan för kommersiellt erhållen MPS och ett outforskat fenomen observerades i fallet med SNP-baserade SCE. Handskbox (GB) prover vid relativ fuktighet (RH)-0,005 % har högre konduktivitet än torrrumsprover vid RH-0,5 %. Dessa resultat kan användas för en framtida referens vid utvärdering av kommersiella MPS-baserade kompositer som fasta elektrolyter.

No description available.

Les supercapacités électrochimiques sont des dispositifs de stockage d’énergie à haute puissance, permettant d’emmagasiner et de relarguer l’énergie très rapidement. Parce qu’ils ne peuvent stocker de grandes quantités d’énergie, ces dispositifs sont souvent utilisés en tandem avec des batteries qui, elles, ont de grandes densités d’énergie. Le stockage d’énergie dans les supercapacités se fait principalement par le déplacement des ions dans la double couche électrique de carbones activés (élaboré par un traitement thermique en base concentrée pour augmenter la taille et la quantité des pores) à haute surface spécifique. La présence de réactions faradiques lors du stockage permettrait d’augmenter l’énergie spécifique des supercapacités et d’en améliorer l’utilisation. L’approche préconisée dans le groupe Rochefort pour arriver à ce but est d’ajouter une espèce redox soluble dans l’électrolyte. Les liquides ioniques redox (donc modifiés avec un centre électroactif) sont particulièrement prometteurs par leur grande solubilité dans les électrolytes à base de solvants organiques. Il y a toutefois bien peu de connaissances sur leur fonctionnement et leurs interactions avec les électrodes de carbone activé. Dans le cadre de ce mémoire, nous avons étudié les interactions entre un liquide ionique redox modifié avec le groupement ferrocène [EMIm][FcNTf] (1-Ethyl-3-methylimidazolium Ferrocénylsulfonyl(trifluorométhylsulfonyl) imide) et deux matériaux en carbone poreux. L’utilisation de deux carbones commerciaux YP-80F et YP-50F, qui ont une des formes de pores semblable, mais des distributions des pores différentes, a permis de mieux comprendre l’effet de la taille des pores sur le stockage. Le carbone avec la plus grande proportion de pores de grande taille allant jusqu’à 3 nm, le YP-80F, a révélé une forte augmentation de l’énergie spécifique de l’ordre de 30 % à 40 % par rapport à celui avec des pores plus restreints (32,9 Wh/kg pour YP-80F contre 19,7 Wh/kg pour YP-50F). Pour déterminer si l’augmentation de l’énergie spécifique est à l’origine d’une meilleure accessibilité des ions redox volumineux aux pores du carbone, nous avons utilisé la spectroscopie de résonance magnétique nucléaire à l’état solide (RMN en 19F). Les études RMN ont montré que le carbone YP-80F, lors de sa charge, contient une plus grande proportion d’ions dans les pores que le YP-50F qui présente des pores de plus petite taille. Ces résultats permettront de développer des espèces électroactives mieux adaptées aux carbones avec lesquels elles sont utilisées et d’améliorer le stockage d’énergie dans les supercapacités électrochimiques. / Electrochemical supercapacitors are high-power energy storage devices that can store and release energy very quickly. Because they cannot store large quantities of energy, these devices are often used in tandem with batteries, which have high energy densities. Energy storage in supercapacitors is mainly achieved by moving ions in the electric double layer of activated carbons with high specific surface area. The addition of faradic reactions during storage would increase the specific energy of supercapacitors and improve their utilization. The approach followed by the Rochefort group to achieve this goal is to add a soluble redox species to the electrolyte of the supercapacitor. Redox ionic liquids (i.e. modified with an electroactive center) are particularly promising because of their high solubility in electrolytes. However, very little is known about how they work and interact with activated carbon electrodes. In this work, we studied the interactions between a redox ionic liquid modified with the ferrocene moiety and two porous carbon materials. Using two commercial carbons YP-80F and YP-50F, which have similar porosity but different pore distributions, we were able to gain a better understanding of the effect of pore size on storage. The carbon with the highest proportion of large pores, YP-80F, showed a strong increase in specific energy of the order of 30% to 40% over that with smaller pores (32,9 Wh/kg for YP-80F vs. 19,7 Wh/kg for YP-50F). Solid-state nuclear magnetic resonance (NMR) spectroscopy was used to determine whether the increase in specific energy was due to greater accessibility of bulky redox ions to the carbon pores. NMR studies have shown that YP-80F carbon, when charged, contains a higher proportion of ions in the porosity than YP-50F, which has a more restricted porosity. These results will enable us to develop electroactive species better suited to the carbons with which they are used, and to improve energy storage in electrochemical supercapacitors.

Metals and valuable metal compounds are important parts of our everyday lives with applications ranging from aluminum foil over circuit boards to high-performance alloys for engineering and buildings construction. Large-scale metal production processes provide access to metals contained in numerous naturally occurring ores, earths and minerals and should be considered one of the major drivers of industrialization, leading to a continuous increase in living standards. Thereby, metals are often present in the form of oxides or other compounds of low reactivity and high stability. This makes metal extraction an often energy-intensive, environmentally problematic endeavor, relying on high reaction temperatures around 1000 °C or aggressive, corrosive and toxic chemicals. A disruptive, new approach for more sustainable metal production could be ionometallurgy, i.e., metal extraction by means of ionic liquids (ILs) and deep eutectic solvents (DESs). ILs, per definition, are salts with a melting point below 100 °C, while DESs are eutectic mixtures of two or more reagents with a melting point below that of the individual components. Both classes of materials feature favorable properties, such as a good solubility for many inorganic salts. Ionometallurgy is a seemingly simple approach, dissolving metal oxides at moderate temperature in an IL or DES and subsequently either electrodepositing the respective metal or producing valuable metal compounds by downstream chemistry. This thesis elucidated the general feasibility of the direct ionometallurgical metal production from metal oxides in two betaine-based solvents, namely the IL betainium bis(trifluoromethylsulfonyl)imide ([Hbet][NTf2]) and a DES consisting of betaine hydrochloride, urea and glycerol in the molar ratio 1 : 4 : 2.5 ([Hbet]Cl/4U/2.5GLY). Initial solubility studies involved a broad screening of the reaction behavior of numerous metal oxides with different properties regarding the position of the metal in the periodic table, its oxidation state as well as the basicity of the oxide. Exploiting the Brønsted-acidic functional group of the betainium cation, metal oxide dissolution in this case follows the principle of an acid-base reaction. Correspondingly, [Hbet][NTf2] favors the dissolution of basic or amphoteric metal oxides, while acidic metal oxides remain unaffected. In-depth investigations were performed for the examples of copper, cobalt and aluminum and identified the metal oxide lattice energy, the crystal structure and the reaction temperature as well as complex stabilities of the metal ions as additional factors to influence the solubility. How additives can affect the reaction outcome in multiple ways was shown for the example of chloride. In the copper system, small amounts of chloride act catalytically, while larger concentrations not only decrease the reaction time but also exhibit a structure-directing effect. For cobalt oxides, chloride is assumed to be reaction-driving due to the high chloride affinity of cobalt(II). These results were supported by seven new crystal structures found in the course of these investigations. Thereby, for the first time, metal oxide dissolution in [Hbet][NTf2] was systematically investigated under water-poor conditions. Abstaining from aqueous IL solutions, although water was shown to promote metal oxide dissolution, enables access to several metals via electrodeposition. This is facilitated by the large electrochemical windows of [Hbet][NTf2] and [Hbet]Cl/4U/2.5GLY, amounting to −2.0–1.4 V and −2.3–0.9 V, respectively. Copper, cobalt, nickel, tin, lead, zinc, and small amounts of vanadium were shown to be electrochemically reducible, whereas manganese, molybdenum and aluminum could not be electrodeposited within the electrochemical stability range of the IL or DES. For the deposition of the noble metal copper, the chloride content, the deposition temperature and additional organic solvents were identified as crucial parameters for the deposition potential as well as the quality of the deposit. By copper-coating a steel plate, a potentially industrially relevant application was demonstrated. Compared to the conventional industrial process for copper production, this ionometallurgical approach could imply a significant simplification and proceed at much lower reaction temperatures. Starting from tenorite or oxidic copper waste, copper coatings could directly be producible avoiding multiple process steps. Furthermore, the cobalt system revealed, that the thorough understanding of the complex equilibria present in solution is crucial for the successful electrodeposition of the metal. Thus, no deposits were obtained when anionic [CoCl4]2– was the predominant cobalt complex species. The adjustment of the cobalt-to-chloride ratio is a suitable method to generate sufficient amounts of cationic cobalt complexes, allowing for the deposition of the metal. Overall, several metals were directly produced from their oxides by the ionometallurgical approach at temperatures below 175 ℃. This means a significant temperature reduction compared to the conventional processes. Encouragingly, [Hbet][NTf2] already showed first promising results when applied to industrially relevant starting materials, such as black mass for the recycling of lithium ion batteries or bauxite as a highly relevant, naturally occurring aluminum resource. While this qualifies ionometallurgy in principle as a considerable improvement regarding process sustainability, the impact of [Hbet][NTf2] and [Hbet]Cl/4U/2.5GLY was analyzed in more depth. Thereby, the recyclability of the solvents is considered a very important factor for the efficient implementation of ionometallurgy in larger scale. First experiments in a two-compartment electrochemical cell showed that metals can be electrodeposited cathodically with a tailorable anode reaction. The oxygen evolution reaction in an aqueous electrolyte proved as suitable benign oxidation reaction in the anode half cell. The intactness of [Hbet][NTf2] after metal electrodeposition in this set-up was evidenced by NMR spectroscopy, qualifying the IL for reuse in principle. As opposed to this, decomposition reactions were identified to take place in both the IL and the DES. At 175 °C, [Hbet][NTf2] undergoes the chloride-induced decomposition via a Hunsdieker and a Deacon reaction, which is avoidable by a lower reaction temperature of 150 °C. NMR studies suggest that [Hbet][NTf2] does not decompose during the ionometallurgical process at this temperature. However, in the case of [Hbet]Cl/4U/2.5GLY, NMR and mass spectrometric studies proved the degradation via several decomposition pathways at 60 °C already. These decomposition reactions change the composition of the DES, which also affects the solubility of metal oxides. The thermal and chemical stability of [Hbet][NTf2] and [Hbet]Cl/4U/2.5GLY, besides other factors, have direct implications for their consideration as green solvents. Thus, [Hbet][NTf2] should only be used at reaction temperatures below 150 °C. Furthermore, its industrial application might be impeded by the expensive and toxic [NTf2]– anion. While betaine-based solvents can be easily accessible due to the natural abundance of betaine, the synthesis effort of the [NTf2]– anion makes [Hbet][NTf2] a considerably expensive IL. [Hbet]Cl/4U/2.5GLY is cheaper and easier to be synthesized from naturally abundant substances, yet not a considerable option due to its decomposition at low temperature already. Its thermal and chemical instability pose hardly surmountable obstacles regarding the recycling and the toxicity of [Hbet]Cl/4U/2.5GLY. Thus, both [Hbet][NTf2] and [Hbet]Cl/4U/2.5GLY do not qualify as green solvents and more benign alternatives should be found in the future. Altogether, this thesis showed that the ionometallurgical production of metals from their oxides is possible and, moreover, could be a sustainable alternative to conventional processes. The presented investigations extend our understanding of metal oxide chemistry in ILs or DESs and provide proofs of concept, laying a foundation for further work that leaves numerous opportunities for ongoing exploration and optimization. Hence, ionometallurgy could be one step to face the urgent challenge of climate change.

No description available.

The convergence of supramolecular and polymer sciences has led to the construction of analogs of traditional covalently-constructed polymeric structures and architectures by supramolecular methods. Host-guest complexations of polymers are also possible through well-defined synthesis of polymeric building blocks, for novel supramolecular polymers. Monotopic polymeric building blocks were synthesized by controlled radical polymerizations with a crown or paraquat initiator. The combinations of terminal and central functionalities of host and guest polymeric building blocks provided chain-extended and tri-armed homopolymers, and diblock and tri-armed copolymers. A supramolecular graft copolymer was formed from a main-chain poly(ester crown ether) and a paraquat terminated polystyrene. This comb-like copolymer was characterized by a large viscosity increase. A four-armed polystyrene-b-poly(n-butyl methacrylate) was synthesized from a pseudorotaxane macroinitiator derived from a complex of a crown-centered polystyrene and a dufunctional paraquat compound. A single peak with higher molecular weight from size exclusion chromatography proved the copolymer formation. Supramolecular interactions enhance the ionic conductivity of semi-crystalline ionic polymers; the ionic conductivity of a C₆-polyviologen and dibenzo-30-crown-10 mixture was 100 times higher than the polyviologen itself. However, ionic conductivities of amorphous polyviologens with polyethers were influenced only by glass transition temperature changes. New imidazolium ionic liquid monomers and imidazolium based polymers were synthesized for potential applications in electroactive devices, such as actuators. Structure-property relationships for pendant imidazolium polyacrylates and main-chain imidazolium polyesters were investigated. Terminal ethyleneoxy moeties enhanced ionic conduction 2~3 times; however, the alkyl chain length effect was negligible. For the imidazoium polyesters, higher ion conductivities result from 1) mono-imidazolium over bis-imidazolium, and 2) bis(trifluoromethanesulfonyl)imide polymers over hexafluorophosphate analogs. A semi-crystalline hexafluorophosphate polyester with C₁₀-sebacate-C₁₀, displayed 400-fold higher ionic conductivity than the amorphous C₆-sebacate-C₆ analogue, suggesting the formation of a biphasic morphology in the former polyester. New dicationic imidazolium salts have interesting features. 1,2-Bis[N-(N'-alkylimidazoilum)]ethane salts stack well in the solid state and possess multiple solid-solid phase transitions. They complex with dibenzo-24-crown-8 and a dibenzo-24-crown-8 based pyridyl cryptand with <i>K_a</i> = ~30 and 360 M¹, respectively. Some of these dicationic imidazolium salts have low entropies of fusion, typical of plastic crystals. These newly discovered imidazolium homopolymers have ionic conductivities up to 10⁴ (S cm⁻¹); however, better properties are still required. Well-designed block copolymers should provide both good electrical and mechanical properties from bicontinuous morphologies, such ion channels. / Ph. D.

Récemment, les liquides ioniques ont attiré l'attention de la communauté scientifique de la catalyse homogène en tant que solvants répondant aux principes de la chimie verte. De par leur nature chargée, ces phases ioniques sont idéales pour des réactions biphasiques avec des substrats organiques et permettent une récupération facile du catalyseur. Leur caractère ionique leur confère une organisation spatiale à l'échelle nanométrique permettant des phénomènes de solvatations particuliers et une réactivité spécifique. Néanmoins, ces solvants continuent à être onéreux et les supporter peut permettre à la fois de réduire de façon significative les quantités utilisées et de récupérer facilement le catalyseur immobilisé dans la phase liquide ionique. Jusqu'à présent, la catalyse supportée sur liquides ioniques a mis en jeu des supports oxydes mésoporeux classiques comme la silice. Au cours de cette thèse, une étude comparative entre ces types de supports et des nanotubes de carbone multiparois a été réalisée pour différentes réactions catalytiques. Les nanotubes de carbone présentent une macrostructure très ouverte avec une mésoporosité importante. Ainsi, la limitation par transfert de masse dans la porosité du support est diminuée et la cinétique de la réaction, augmentée. Une première étape de fonctionnalisation des nanotubes de carbone a permis d'améliorer la compatibilité avec la phase liquide ionique. L'immobilisation stabilise le catalyseur (complexe métallique [Rh(nbd)(PPh3)2][PF6] ou nanoparticules de palladium) dans la phase liquide ionique après formation d'un film autour des nanotubes. Les systèmes catalytiques supportés ont été utilisés pour différentes réactions tests : l'hydrogénation, le couplage C-C de Heck et la réaction séquentielle Heck/hydrogénation. Des composites supports oxydes (SiO2 ou Al2O3)/liquide ionique ont été préparés afin d'étudier les interactions spécifiques liquide ionique-surface et les comparer avec le liquide ionique pur. / As catalytic support, carbon nanotubes present an open macrostructure with large mesoporosity which avoids mass transfer limitations. Ionic Liquids (ILs) have received much attention in the past years due to their importance in a broad range of applications. In catalysis, they are used to immobilize the catalyst in biphasic reactions and enable an easy separation. Their ionic character confers to these media a special organization of several nanometers that induces solvation phenomena and specific reactivity that can be linked either to confinement effects in the organized structure or to molecular interactions. However, these solvents remain expensive and the fact to support them onto carbon nanotubes as a thin film should permit to reduce significantly the volumes used. In this PhD thesis in order to prepare carbon nanotubes-IL hybrid materials, multi-walled carbon nanotubes were covalently modified with imidazolium salt-based moieties. This functionalization allowed specific interactions between the IL thin film and the chemical moieties on the MWCNTs surface. Then, the catalyst (rhodium complex or palladium nanoparticles) was immobilized into the IL thin film. The catalytic performances have been evaluated in bench reactions: hydrogenation of 1-hexene for rhodium, and selective hydrogenation, Heck, and sequential Heck/hydrogentation process for palladium. Finally, a comparative study has been performed between carbon nanotubes and other classical mesoporous oxide supports, including silica. The carbon nanotubes based catalyst present better performances than their counterparts prepared on conventional supports. Additionally, composites based on SiO2/IL or Al2O3/IL were prepared to carry out a structural study with the aim of understanding their specific surface interactions and compare them to pure ionic liquid.

Les propriétés d'une nouvelle classe de chimie de surface basée sur les monocouches auto-assemblées de liquides ioniques (ILs-SAMs), ont été étudiées pour une utilisation dans la construction de biocapteurs basés sur la résonance des plasmons de surface (SPR). Les biocapteurs sont utiles pour détecter des biomolécules spécifiques dans une matrice biologique complexe. Cependant, le signal analytique de la biomolécule spécifique peut être masqué par l’adsorption non spécifique de la matrice biologique, produisant une réponse faussement positive. Par ailleurs, l'activité des récepteurs moléculaires est souvent réduite par des techniques d'immobilisation chimique. Ainsi, il est essentiel de déterminer une surface idéale pour la préparation de biocapteurs. Les liquides ioniques sont bien connus pour favoriser l'activité des récepteurs moléculaires et cette étude enquête si cette propriété importante peut se traduire sur des capteurs SPR. Différents liquides ioniques ont été utilisés pour former des monocouches auto-assemblées sur une surface d'or. Les ILs-SAMs sont tous basés sur les sels de mercapto-(chaîne alkyle)nCH2-méthylimidazolium avec différentes chaînes alkyles (n = 3, 6, 9, 12) et différents contre-anions (Br-, BF4-, PF6-, NTf2-). Des études cinétiques de l'adsorption non spécifique de sérum bovin ont été réalisées sur des capteurs SPR avec un instrument construit sur mesure, basé sur l'interrogation des longueurs d’ondes SPR sur un prisme d’inversion d’image (dove). Par la suite, l’anti-IgG de chèvre sélective à l’IgG humain a été utilisé en tant que modèle pour la confection de biocapteurs sur les ILs-SAMs. En solution, il est possible d’effectuer des échanges du contre-anion des liquides ioniques pour un contre-anion de plus en plus hydrophobe. Cependant, l’échange inverse, soit vers des anions de plus en plus hydrophile, s’avère impossible. Toutefois, il a été observé par les travaux présentés dans ce mémoire, que les liquides ioniques immobilisés sur une surface d'or ont la capacité d'échanger leurs contre-anions réversiblement, procurant une méthode simple de moduler leurs propriétés physico-chimiques. Ce phénomène a été observé par la mesure d’angles de contacts et par les techniques spectroscopiques de l’infrarouge moyen (mid-IR), des photoélectrons de rayon-X (XPS) et par la diffusion Raman exaltée par les surfaces (SERS) ii ainsi que par la spectrométrie de masse (MS). La connaissance des propriétés d’échange d’anion est importante pour prédire le comportement de ces surfaces de liquides ioniques dans les tampons et fluides biologiques. / The properties of a novel class of surface chemistry based on ionic liquid self-assembled monolayers (IL-SAM) were investigated for use with surface plasmon resonance (SPR) biosensors. Biosensors are useful to detect specific biomolecules in a complex biological matrix. However, the analytical signal of a specific biomolecule can be masked by nonspecific adsorption of the biological matrix, resulting in a false positive response. Moreover, the activity of molecular receptors is often reduced by current immobilization chemistry. Thus, it is essential to determine an ideal surface for the preparation of biosensors. Ionic liquids are well-known to promote the activity of molecular receptors and this study investigates if this important property translates to SPR sensors. Different ionic liquids were used to form self-assembled monolayers on a gold surface. IL-SAM were based on mercapto(alkyl chain)n methylimidazolium salts with different alkyl chain (n = 3, 6, 9, 12) and counter anions (Br-, BF4-, PF6-, NTf2-). Kinetic studies of the nonspecific adsorption of bovine serum were carried on SPR sensors with a custom built instrument based on wavelength interrogation SPR on a dove prism. Thereafter, anti-goat IgG selective to human IgG was used as a model for biosensor employing ILs-SAM surface chemistry. Exchange of counter anion of ionic liquids was believed impossible for most hydrophobic counter anions. However, it was observed that ionic liquids immobilized on a gold surface have the ability to exchange their counter anions reversibly, allowing a simple method to modulate their physico-chemical properties. This phenomenon was observed by contact angle technique and by attenuated total reflectance mid-infrared (ATR mid-IR), X-ray photoelectron spectroscopy (XPS), surface enhanced raman spectroscopy (SERS) and mass spectrometry (MS). Better understanding of the anion exchange properties is crucial in predicting the behaviour of IL-SAM in presence of biological buffers and fluids.

L’objectif de ce travail est d’étudier et de contribuer à améliorer la capacité des liquides ioniques pour l’absorption sélective de dioxyde de carbone. Pour cela nous avons envisagé la fluorination partielle des cations ou des anions constituant les liquides ioniques. Nous avons sélectionné des liquides ioniques partiellement fluorés à étudier, dont trois ont été synthétisés dans ce travail. Dans un premier temps, nous avons étudié l’impact de la structure des liquides ioniques purs sur leurs propriétés thermophysiques telles que la masse volumique, la viscosité et la stabilité thermique. Dans un deuxième temps, nous avons étudié les propriétés thermodynamiques de mélanges des liquides ioniques avec des gaz ou des liquides. La miscibilité de l’eau a ainsi été étudiée en fonction de la température. Nous avons mesuré la solubilité de cinq gaz (dioxyde de carbone, protoxyde d’azote, éthane, azote, hydrogène) dans les liquides ioniques, pour des températures comprises entre 298 K et 343 K et des pressions proches de la pression atmosphérique. La simulation moléculaire a été utilisée afin d’identifier les sites préférentiels de solvatation de dioxyde de carbone et d’éthane, et de proposer des mécanismes moléculaires de solvatation de ces gaz. Les coefficients de diffusion du dioxyde de carbone et de l’éthane dans les liquides ioniques ont été calculés. Nous avons déterminé l'enthalpie de solution et la limite de solubilité du dioxyde de carbone en fonction de la pression à 313 K utilisant une technique calorimétrique à écoulement. / The research project of this thesis is devoted to the evaluation of the use ionic liquids for applications in carbon dioxide separation and capture. The objective of this work is to improve the ability of ionic liquids to selectively absorb carbon dioxide by partially fluorinating the alkyl chains on the cation and / or the anion. First, we selected the ionic liquids to study and we had to synthesize three ionic liquids.Then, the first part of our studies is focused on the impact of the structure of pure ionic liquids on their thermophysical properties. Density, viscosity and thermal stability were determined. The second part of our studies deals with the determination of the thermodynamic properties of solution of gaseous solutes and liquids in ionic liquids. The miscibility gap in mixtures of ionic liquids with water was studied as a function of temperature. We have determined experimentally the solubility of five gases (carbon dioxide, nitrous oxide, ethane, nitrogen and hydrogen) in Ionic liquids for temperatures between 298 K and 343 K and pressures close to atmospheric pressure. Molecular simulation tools were used in order to identify the preferential solvation sites of carbon dioxide and ethane in ionic liquids and we have proposed the molecular mechanisms of solvation. Moreover, the diffusion coefficient of carbon dioxide and ethane in some ionic liquids was investigated. Finally, we studied as a function of the pressure, at 313 K, the enthalpy of solution and the solubility limit of carbon dioxide in two ionic liquids, using a flow calorimetric technique.