Les solutions de micelles géantes sont utilisées dans plusieurs domaines industriels pour augmenter la viscosité d'une solution. Elles présentent un caractère viscoélastique bénéfique pour la fracturation hydraulique des roches pétrolifères car elles permettent de transporter le sable et de le maintenir en suspension. Cette thèse étudie les propriétés rhéologiques d’une solution commerciale destinée à la fracturation hydraulique. Cette solution est particulièrement délicate à caractériser car ses écoulements semblent être toujours instables. Nous avons mis au point une méthodologie permettant de la caractériser en régime laminaire, et avons montré que ce régime n’existe à température ambiante que pour des très faibles valeurs de taux de cisaillement. Habituellement, le comportement rhéologique dans le régime linéaire de ce type de solution est prédit par le modèle de Maxwell. Nous mettons en évidence que le comportement rhéologique de la solution étudiée ne correspond pas à ce modèle. Nous avons établi un modèle viscoélastique compatible avec les données expérimentales.Les instabilités d’écoulement de ces solutions sont d’origine élastique. Ce phénomène est largement étudié dans la littérature. Le comportement rhéologique dans le domaine non linéaire possède des caractéristiques propres à ces solutions. Notamment l’apparition d’un plateau de contrainte dans la courbe d’écoulement, précédé par une augmentation linéaire de la contrainte avec le cisaillement. Le début de ce plateau coïncide avec le déclenchement des instabilités, on parle de taux de cisaillement critique. La particularité de cette solution est la valeur faible de la contrainte plateau ainsi que du taux de cisaillement critique. Les valeurs observées sont cohérentes avec la valeur des paramètres rhéologiques obtenus dans les régimes d’écoulement laminaire. L’effet de certains paramètres physico-chimiques sur la rhéologie est également exploré. / Giant micelle solutions are used in several industrial domains to increase the viscosity of solution. Their viscoelastic characteristic is beneficial for hydraulic fracturing of oil rocks because these solutions are able to transport sand and to keep it in suspension. This thesis examines the rheological properties of a commercial solution, designed for hydraulic fracturing. This solution is particularly difficult to characterize because its flows seem to be always unstable. We have developed a methodology to characterize it in the laminar regime and we have shown that this regime exists at room temperature only for very low shear rate values. Usually, the rheological behavior of this type of solution, in the linear regime, is predicted by the Maxwell model. We prove that the rheological behavior of the studied solution doesn’t match this model. We have designed a viscoelastic model that is compatible with experimental data.The origin of flow instabilities of these solutions is elastic. This phenomenon is widely studied in the literature. The rheological behavior in the nonlinear regime has characteristics specific to these solutions. In particular, the appearance of a stress plateau in the flow curve, preceded by a linear increase of stress with shear. The beginning of this plateau match the onset of instabilities at a critical shear rate. The feature of this solution is the low value of the stress plateau as well as the critical shear rate value. They are consistent with the value of rheological parameters obtained in laminar flow regimes. The effect of some physico-chemical parameters on rheology is also explored.

This study aims synthesis of metal/polymer one dimensional nanostructures by micelle formation, reduction, and electrospinning route, and to analyze the morphological characteristics of composite nanofibers. The study was carried out in three main steps. First, the reverse micelle structures were established between the anionic surfactant and the metal ion. The surfactant acts as an agent to bind metal ions together so that the arrangements of metal ions can be controlled in the solution. As the surfactant concentration increases, reverse micelles grow and reverse wormlike micelle structures are observed. Wormlike micelles are elongated semi flexible aggregates which form a spherocylinder form repeating units. Metal ions are in the core and surrounded with the surfactant. The polymer attached to the wormlike structure acts as a shield and prevents phase separation in a hydrophilic medium. Different polymer and surfactant concentrations were tried to determine the optimum polymer and surfactant concentrations for reverse micelle formation. The size analyses of the reverse micelle structures were done by dynamic light scattering technique. In the second step, metal ions in the micelles were reduced by using hydrazine hydrate to obtain metal cores in the center of wormlike micelles. Finally, electrospinning was carried at room temperature and in air atmosphere. The characterization of nano composites was done by Scanning Electron Microscopy. It was found that the size of the reverse micelle structures affects the distribution of metal nano partices in polymer nano fibers. In order to distribute the metal nano particles homogeneously, the optimum size of reverse wormlike micelles was found to be between 420 and 450 nm.

Investigation and characterization of polymeric materials are necessary to obtain in-depth understanding of their behavior and properties, which can fuel further development. To illuminate these molecular properties and their coupling to macroscopic behavior, we have performed nuclear magnetic resonance (NMR) studies on a variety of chemical systems. In addition to versatile "traditional" NMR measurements, we took advantage of specialized techniques, such as "rheo-NMR," 2H NMR, and NMR self-diffusion experiments to analyze alignment, orientational order, elaborate rheological behavior, and ion transport in polymer films and complex fluids. We employed self-diffusion and quadrupolar deuterium NMR methods to water-swollen channels in Nafion ionomer films commonly used in fuel cells and actuators. We also correlated water uptake and anisotropic diffusion with differing degrees and types of alignment in Nafion films based on membrane processing methods. Further, we made quantitative measurements of bulk channel alignment in Nafion membranes and determined anisotropic properties such as the biaxiality parameter using these methods. Additionally, our studies made the first direct comparison of directional transport (diffusion) with quantitative orientational order measurements for ionomer membranes. These results lend insight to the importance of water content in ionomer device performance, and showed that increased control over the direction and extent of orientational order of the hydrophilic channels could lead to improved materials design. We used the same techniques, with the addition of "rheo-NMR" and solution rheology measurements, to study the complex rheological behavior of cetyltrimethylammonium bromide wormlike micelle solutions, which behave as nematic liquid crystals at sufficiently high concentration. Amphiphilic solutions of this type are used in myriad applications, from fracturing fluids in oil fields to personal care products. We investigated the phase behavior and dynamics of shear and magnetic field alignment, and made the first observations of a novel bistable shear-activated phase in these solutions. Our first reports of the complex Leslie-Ericksen viscoelastic parameters in wormlike micelles and measurements of diffusion anisotropy show the potential for increased control and understanding of materials used in tissue engineering, oil extraction, personal care products, and advanced lubricants. / Ph. D.