Water solutions of high molecular weight polymer, made up of deformable objects in solution, are usually used for oil recovery applications. These viscoelastic fluids generally display an important interfacial slip which dominates their rheological properties at sub-micron scales. The understan- ding of this phenomenon is necessary to account for the behaviors observed during their flow within nanoporous mediums, such as oil tanks walls.<br/>We study the interfacial hydrodynamics of polyelectrolyte solutions of high molecular weight thanks to nanorheology experiments carried out with a home-made surface force apparatus. During these experiments, the hydrodynamic boundary condition is investigated by studying the drainage flow of these confined solutions brought about by the approach of the confining solid walls. Confinement can be continuously modified from fifteen micrometers to the contact between the walls. The measurement of the normal viscoelastic forces exerted on the walls is interpreted using the theoretical model we develop. We show that the hydrodynamic boundary condition is complex and exhibits a complex slip length. When confinement is larger than the size of the macromolecules, these forces behavior gives us access to the viscoelastic properties of the solutions. Thanks to the study of these forces at sub-micron scale, we determine the microscopic origin for the apparent slip we observe.

Nanorhelogy of complex fluids at interfaces: Bulk behavior and complex slip length

253rd National Meeting (2017)

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