Stress Enhancement in the Delayed Yielding of Colloidal Gels

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Fig1 Stress Enhancement.jpg

Summary

Networks of aggregated colloidal particles are solidlike and can sustain an applied shear stress while exhibiting little or no creep; however, ultimately they will catastrophically fail. It is shown here that the time delay for this yielding decreases in two distinct exponential regimes with applied stress. This behavior is universal and found for a variety of colloidal gel systems. A bond-rupture model is presented that quantitatively describes this behavior and highlights the role of mesoscopic structures, giving new insight into the nature of yielding in these soft solid materials.