Yuli Wei1, G. Seevaratnam1, S. Garoff1, E. Rame2, and Lynn M. Walker1. (1) Carnegie Mellon University, Pittsburgh, PA, (2) National Center for Space Exploration Research, Cleveland, OH
The impact of fluid elasticity on the dynamic wetting of polymer solutions is important because many polymer solutions in technological use exhibit non-Newtonian behaviors in the high shear environment of the wedge-like flow near a moving contact line. Our former study showed that shear thinning induced by a semi-flexible high molecular weight polymer reduces the viscous bending near a moving contact line as compared to a Newtonian fluid having the same zero-shear viscosity. This results in a dramatic reduction of the dependence of the effective dynamic contact angle on contact line speed. In this talk, we discuss dynamic wetting of Boger fluids which exhibit elasticity dominated rheology with minimal shear thinning. These fluids are prepared by dissolving a dilute concentration of high molecular weight polymer in a “solvent” of the oligomer of the polymer. We demonstrate that elasticity in these fluids increases curvature near the contact line but that the enhancement arises mostly from the weakly non-Newtonian behavior already present in the oligimeric solvent.