645 research outputs found
Dynamics of a colloidal glass during stress-mediated structural arrest
We employ parallel superposition rheology to study the dynamics of an aging
colloidal glass in the presence of a mean field stress. Over a range of
intermediate stresses, the loss modulus exceeds the storage modulus at short
times but develops a maximum concomitant with a crossover between the two as
the system ages. This is attended by a narrowing of the loss peak on increasing
stress. We show that this feature is characteristic of the structural arrest in
these materials, which is made observable on reasonable timescales by the
activating influence of the stress. The arrest time displays an exponential
dependence on inverse stress. These results provide experimental validation of
the role of stress as an effective temperature in soft glassy systems as has
been advanced in recent theoretical frameworks.Comment: 5 pages, 5 figure
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