Dynamics of internal stresses and scaling of strain recovery in an aging colloidal gel

We monitor the relaxation of internal stresses in a fractal colloidal gel on cessation of flow and find a weak power-law decay, sigma(i)similar to t(-alpha) over five decades of time where alpha approximate to 0.07. The system exhibits physical aging of the elastic modulus, G'similar to t(beta), with beta approximate to alpha. Imposition of zero stress after waiting time t(w) results in strain recovery as the system relaxes without constraint. Remarkably, recoveries at different t(w) can be shifted to construct a master curve where data are scaled vertically by 1/sigma(i)(t(w)) and plotted horizontally as (t-t(w))/t(w)(mu), where mu approximate to 1.25, indicative of a superaging response.