Migration of semiflexible polymers in microcapillary flow

TL;DR

This study investigates how semiflexible polymers behave and migrate within microchannels under flow, revealing flow-dependent conformations, orientation-driven migration, and tumbling dynamics through mesoscale simulations.

Contribution

It provides new insights into the flow-induced conformations and migration mechanisms of semiflexible polymers confined in microchannels, highlighting the role of hydrodynamic interactions.

Findings

Polymers show U-shaped conformations near the channel center.

Hydrodynamic interactions cause strong cross-streamline migration.

Tumbling time depends on Peclet number similarly to shear flow.

Abstract

The non-equilibrium structural and dynamical properties of a semiflexible polymer confined in a cylindrical microchannel and exposed to a Poiseuille flow is studied by mesoscale hydrodynamic simulations. For a polymer with a length half of its persistence length, large variations in orientation and conformations are found as a function of radial distance and flow strength. In particular, the polymer exhibits U-shaped conformations near the channel center. Hydrodynamic interactions lead to strong cross-streamline migration. Outward migration is governed by the polymer orientation and the corresponding anisotropy in its diffusivity. Strong tumbling motion is observed, with a tumbling time which exhibits the same dependence on Peclet number as a polymer in shear flow.