Active and nonlinear microrheology in dense colloidal suspensions.
We present a first-principles theory for the active nonlinear microrheology of colloidal model system; for a constant external force on a spherical probe particle embedded in a dense host dispersion, neglecting hydrodynamic interactions, we derive an exact expression for the friction. Within mode-coupling theory, we discuss the threshold external force needed to delocalize the probe from a host glass, and its relation to strong nonlinear velocity-force curves in a host fluid. Experimental microrheology data and simulations, which we performed, are explained with a simplified model.
Gazuz
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I
Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany.
Puertas
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Voigtmann
Th
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Fuchs
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