Scaling of the dynamic response of hectorite clay suspensions containing poly(ethylene glycol) along the universal route of aging

The temporal growth of dynamic response during the aging of hectorite clay suspensions containing NaCl with different poly(ethylene glycol) (PEG) concentrations was measured. For each PEG concentration, the dynamic responses at different waiting times were shifted into a master curve against the rescaled frequency, which indicated that the dynamic spectrum was preserved during the aging process. At each fixed waiting time, the dynamic responses of suspensions with different PEG concentrations were also shifted into a master curve against the rescaled frequency, which revealed that the modification of inter-particle interaction by the PEG adsorption did not change the relaxation during the aging route. These two superposition approaches led to a universal master curve revealing the equivalent effect of PEG concentration and waiting time on the dynamic response. Finally, the relative mean relaxation time extracted from the master curves of waiting time and PEG concentration reflecting the slowing down of the dynamics during aging was superimposed to a master curve, implying the existence of a similar dynamic response. The present results suggested that the universal route of aging was preserved for the clay suspensions and a similar dynamic response was found from the mechanical spectra at different aging stages.