Abstract
Using mode-coupling theory, we derive a constitutive equation for the nonlinear rheology of dense colloidal suspensions under arbitrary time-dependent homogeneous flow. Generalizing previous results for simple shear, this allows the full tensorial structure of the theory to be identified. Macroscopic deformation measures, such as the Cauchy-Green tensors, thereby emerge. So does a direct relation between the stress and the distorted microstructure, illuminating the interplay of slow structural relaxation and arbitrary imposed flow. We present flow curves for steady planar and uniaxial elongation and compare these to simple shear. The resulting nonlinear Trouton ratios point to a tensorially nontrivial dynamic yield condition for colloidal glasses.
- Received 30 April 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.138301
©2008 American Physical Society
Viewpoint
How colloidal dispersions relax under stress
Published 22 September 2008
A shear force can melt a colloidal glass, causing it to flow in a highly nonlinear fashion. Physicists have now found a way to put the description of this type of flow on a more formal theoretical footing.
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