Computer Simulations of Structure, Dynamics, and Phase Behavior of Colloidal Fluids in Confined Geometry and under Shear (A05)

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Two types of colloidal systems exposed to shear deformation will be studied, a modelfor colloid-polymer mixtures under confinement, and a glass-forming binary soft spheremixture. Polymers are described as soft spheres weakly interacting with each other,while colloid-polymer and colloid-colloid pairs interact with the (repulsive) Weeks-Chandler-Andersen potential, so that a depletion attraction between colloids results,similar to the Asakura-Oosawa model. Confining this system between parallel plates,the interplay between phase separation and shear will be studied by Non-EquilibriumMolecular Dynamics, including the suppression of capillary waves at confined interfacesby the shear. Confinement in cylindrical geometry will also be considered. Theglass forming mixture is described by particles interacting with Yukawa potentials, andshear is implemented via Lees-Edwards boundary conditions. The study of transienttime-dependent phenomena will be extended to systems under oscillatory shear and tosystems that are subject to a constant shear stress. The latter problem is the macrorheologicalcounterpart to the micro-rheological simulation of a pulled probe particle,thus enabling to elucidate the relation between micro- and macro-rheology. The resultsof the simulation will be compared to those from mode-coupling theory and experiment.