Aging and nonlinear rheology in suspensions of polyethylene oxide-protected silica particles.

In an attempt to establish connections between classical rheology and aging in paste colloidal suspensions, we report in this paper a large set of experimental results on a given system. We have studied suspensions of polyethylene oxide-protected silica particles and performed classical rheology experiments that exhibit a very nonlinear behavior. We have then evidenced aging through stress relaxation as observed in various glassy systems, and finally show other manifestations of aging through various rheological experiments. Qualitative agreement between these experimental results and the predictions of a simple model suggests that the behavior observed experimentally is governed by the competition between aging and mechanically induced rejuvenation.