Electrokinetically enhanced cross-stream particle migration in viscoelastic flows

Abstract

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Multiphysics microfluidics for cell manipulation and separation: a review

“…Choudhary et al 252 discovered an opposite migration phenomenon due to EP effects in PEO solution. When electrophoresis is in the opposite direction to the main flow, the polystyrene spheres migrate to the centerline instead of the wall region.…”

On the cross-streamline lift of microswimmers in viscoelastic flows

“…The methodology of evaluating the lift velocity closely follows the recent analysis of Choudhary et al 43 . Here, we only summarize the basics and elaborate on details in the ESI.…”

“…The study suggested that the hydrodynamic disturbances around the particle produces a hoop stress that, in the presence of non-uniform shear rate, generates a cross-streamline lift. Recent progress in electrophoresis [42][43][44] has also shed light on the importance of hydrodynamic disturbances in determining these lift forces.…”

“…( 3) in this expansion: the Stokes equation for the zeroth order of the disturbance field, − ∇p0 + ∇2 v0 = 0, and − ∇p1 + ∇2 v1 = − ∇•s0 for the first order. Following earlier works on viscoelastic lift 41,43 , we use the reciprocal theorem to attain the lift velocity from the first-order problem,…”

“…The bounding channel walls modify these bulk flow fields. However, by using the method of reflections for small particles (κ ≪ 1), one can show that they do not alter the lift velocity in leading order in κ 43 . Therefore, it is sufficient to perform the integration in Eq.…”