Flow-Induced Helical Coiling of Semiflexible Polymers in Structured Microchannels

TL;DR

This study uses mesoscale simulations to reveal how semiflexible polymers undergo a flow-induced rod-to-helix transition in structured microchannels due to non-equilibrium buckling, influenced by channel geometry and flow conditions.

Contribution

It demonstrates the mechanism of flow-induced helix formation in semiflexible polymers within microchannels, highlighting the role of non-stationary buckling under flow-induced forces.

Findings

Polymer undergoes a rod-to-helix transition in flow.

Helix properties depend on channel diameter ratio, rigidity, and flow strength.

Flow-induced buckling causes transient helix formation.

Abstract

The conformations of semiflexible (bio)polymers are studied in flow through geometrically structured microchannels. Using mesoscale hydrodynamics simulations, we show that the polymer undergoes a rod-to-helix transition as it moves from the narrow high-velocity region into the wide low-velocity region of the channel. The transient helix formation is the result of a non-equilibrium and non-stationary buckling transition of the semiflexible polymer, which is subjected to a compressive force originating from the fluid-velocity variation in the channel. The helix properties depend on the diameter ratio of the channel, the polymer bending rigidity, and the flow strength.