Synthèse et caractérisation de polymères amphiphiles très hydrophobes anioniques et application au contrôle de la rhéologie de fluides complexes

This work deals with the influence of the hydrophobic modification on the solution properties in water of an alternated copolymer based on styrene and maleic anhydride. It appears that a wide range of hydrophobic content can be covered keeping the solubility in water of the hydrophobically modified copolymers. With increasing the hydrophobic content, the sequence: polyelectrolyte/associating polymers/polysoaps/microgels has been discriminated thanks to the use of scattering techniques combined with rheological measurements. The more hydrophobic system draws a special attention since its properties may be reminiscent of what is encountered with concentrated colloidal dispersions, for instance the solutions exhibit yield stress values. This latter fact has been attributed to the formation of microgel like particles that form a gel once they have filled the whole space. Interestingly, the value for the concentration where the closed packing is reached may be varied by playing with external parameter (temperature, salt, charge content...) that deeply affect the volume fraction of the microgel. The presence of yield stress values makes these systems valuable for oil recovery.Au cours de ce travail, nous nous sommes intéressés à l'influence de la modification hydrophobe sur les propriétés en solution aqueuse d'un copolymère alterné de styrène et d'anhydride maléique. La chimie mise en œuvre garantit de couvrir une large gamme de taux de modification hydrophobe tout en permettant de conserver la solubilité des systèmes. Des mesures combinées de diffusion de rayonnement et de rhéologie ont permis de mettre en œuvre pour ces polyélectrolytes modifiés hydrophobiquement la séquence: polyélectrolyt