Studying polymer diffusiophoresis with Non-Equilibrium Molecular Dynamics

TL;DR

This study uses non-equilibrium molecular dynamics simulations to explore how short polymers move in response to solute concentration gradients, revealing non-monotonic mobility behavior and weak chain length dependence.

Contribution

It provides new insights into polymer diffusiophoresis, highlighting differences from solid particles and the effects of monomer-solute interactions.

Findings

Mobility varies non-monotonically with monomer-solute interaction strength.

Weak dependence of mobility on polymer chain length.

Hydrodynamic flow through polymers is less screened than pressure-driven flows.

Abstract

We report a numerical study of the diffusiophoresis of short polymers using non-equilibrium molecular dynamics simulations. More precisely, we consider polymer chains in a fluid containing a solute which has a concentration gradient, and examine the variation of the induced diffusiophoretic velocity of the polymer chains as the interaction between the monomer and the solute is varied. We find that there is a non-monotonic relation between the diffusiophoretic mobility and the strength of the monomer-solute interaction. In addition we find a weak dependence of the mobility on the length of the polymer chain, which shows clear difference from the diffusiophoresis of a solid particle. Interestingly, the hydrodynamic flow through the polymer is much less screened than for pressure driven flows.