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Understanding nonequilibrium interactions of multi-component colloidal suspensions is critical for many dynamical settings such as self assembly and material processing. A key question is how internal timescales of the suspension couple with driving forces to control nonequilibrium structure and flow behavior. In this work, we develop a first-principle framework to study a bidisperse suspension of colloids and depletants using a Smoluchowski equation and corroborated by Brownian Dynamics (BD) simulations. Using nonlinear microrheology as a case study, we demonstrate that effective depletion interactions between driven colloids are sensitive to particle timescales out of equilibrium and cannot be predicted by equilibrium-based pair potentials like Asakura-Oosawa. Furthermore, we show that the interplay between Brownian relaxation timescales of different species play a critical role in governing the viscosity of multi-component suspensions. Our model highlights the limitations of using equilibrium pair potentials to approximate interparticle interactions in nonequilibrium processes such as hydrodynamic flows and presents a useful framework for studying the transport of multi-component interacting suspensions.

Research Interests:

Multi-component fluids, soft materials, rheology, numerical modelling, molecular simulations, bioinspired systems.