Molecular transport and flow past hard and soft surfaces: Computer simulation of model systems

TL;DR

This paper uses molecular dynamics and single-chain-in-mean-field simulations to study how polymer liquids behave and flow on both hard and soft surfaces, providing parameters for continuum models.

Contribution

It introduces a multiscale simulation approach to characterize polymer-liquid interactions with hard and soft substrates, linking molecular details to continuum descriptions.

Findings

Determined surface and interface tensions from molecular simulations.

Extracted hydrodynamic boundary condition parameters.

Validated continuum models with molecular simulation data.

Abstract

The properties of polymer liquids on hard and soft substrates are investigated by molecular dynamics simulation of a coarse-grained bead-spring model and dynamic single-chain-in-mean-field (SCMF) simulations of a soft, coarse-grained polymer model. Hard, corrugated substrates are modelled by an FCC Lennard-Jones solid while polymer brushes are investigated as a prototypical example of a soft, deformable surface. From the molecular simulation we extract the coarse-grained parameters that characterise the equilibrium and flow properties of the liquid in contact with the substrate: the surface and interface tensions, and the parameters of the hydrodynamic boundary condition. The so-determined parameters enter a continuum description like the Stokes equation or the lubrication approximation.