Shear Thickening in a Solution Undergoing Inverse Melting

International audienceRheological measurements on a solution undergoing inverse melting are presented as a function of temperature and concentration. This solution under shear exhibits the phenomenon of shear thickening, an increase of apparent viscosity with increase in shear rate . In particular a shear thickening transition happens at a critical shear rate which increases with increasing concentration. It defines two different regimes: at low shear rates the fluid shows Newtonian behavior, while at shear rates a transition from the Newtonian to the shear thickening regime is observed. This behaviour is interpreted on the basis of a relaxation process activated by the shear and characterized by a relaxation time . In the thickening region the viscosity data are well fitted with a power law model eta(gammadot) = A*gammadot^(n-1) with n=1.8. The temperature and concentration behaviour of the zero shear viscosity, the power law exponent, the critical shear rate is discusse