Reverse non-equilibrium molecular dynamics simulations of a melt of Kremer-Grest type model under fast shear

TL;DR

This study systematically evaluates the reverse non-equilibrium molecular dynamics (RNEMD) method for simulating a Kremer-Grest type polymer melt under shear, confirming its validity and limitations in capturing inhomogeneities and rheological properties.

Contribution

First systematic assessment of RNEMD applicability to unentangled polymer melts, comparing results with traditional methods and analyzing inhomogeneity effects.

Findings

Temperature and density become inhomogeneous at high shear rates.

Average viscosity aligns with SLLOD method results despite inhomogeneities.

Polymer conformation remains unaffected by temperature-density variations.

Abstract

Although the reverse non-equilibrium molecular dynamics (RNEMD) simulation method has been widely employed, the range of applicability is yet to be discussed. In this study, for the first time, we systematically examine the method against an unentangled melt of the Kremer-Grest type chain. The simulation results indicate that as the shear rate increases, the temperature and density become inhomogeneous. However, the average viscosity remains consistent with the results obtained using the SLLOD method under homogeneous temperature and density. We also confirm that the temperature-density inhomogeneity does not significantly affect polymer conformation.