Impact of random obstacles on the dynamics of a dense colloidal fluid
arXiv:1007.0429 · doi:10.1103/PhysRevE.82.041505
Abstract
Using molecular dynamics simulations we study the slow dynamics of a colloidal fluid annealed within a matrix of obstacles quenched from an equilibrated colloidal fluid. We choose all particles to be of the same size and to interact as hard spheres, thus retaining all features of the porous confinement while limiting the control parameters to the packing fraction of the matrix, Φm, and that of the fluid, Φf. We conduct detailed investigations on several dynamic properties, including the tagged-particle and collective intermediate scattering functions, the mean-squared displacement, and the van Hove function. We show the confining obstacles to profoundly impact the relaxation pattern of various quantifiers pertinent to the fluid. Varying the type of quantifier (tagged-particle or collective) as well as Φm and Φf, we unveil both discontinuous and continuous arrest scenarios. Furthermore, we discover subdiffusive behavior and demonstrate its close connection to the matrix structure. Our findings partly confirm the various predictions of a recent extension of mode-coupling theory to the quenched-annealed protocol.
16 pages, 20 figures, minor revisions
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Cited by in corpus (14)
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- Mode-coupling theory predictions for the dynamical transitions of the partly pinned fluid systems
- Dynamic arrest of colloids in porous environments: disentangling crowding and confinement
- Glassy dynamics of partially pinned fluids: an alternative mode-coupling approach
- Anomalous transport of a tracer on percolating clusters
- Dynamic arrest in model porous media -- intermediate scattering functions
- Nonergodicity parameters of confined hard-sphere glasses
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