Linear Viscoelastic Behavior of Unentangled Polymer Melts via Non-Equilibrium Molecular Dynamics

✍ Scribed by José Gines Hernández Cifre; Siegfried Hess; Martin Kröger

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 163 KB
• Volume: 13
• Category: Article
• ISSN: 1022-1344
• DOI: 10.1002/mats.200400021

✦ Synopsis

Abstract

Summary: We present and assess the use of non‐equilibrium molecular dynamics (NEMD) simulation method for the direct study of the linear viscoelastic behavior of polymer melts. The polymer melt is modeled by a collection of repulsive, anharmonic multibead chains subjected to small amplitude oscillatory shear flow. We present results for chain lengths below the critical entanglement length and obtain good agreement with theoretical results for the viscoelastic behavior of melts of low molecular weight. The range of oscillation frequencies attainable in the simulation is of a few decades. Thus we use, as in experiments, a time‐temperature superposition rule to extend the frequency domain. As a side result, we confirm the so‐called Cox‐Merz rule.

Snapshot from a non‐equilibrium molecular dynamics (3D) simulation of a polymer melt with 100 chains and 40 beads.

magnified imageSnapshot from a non‐equilibrium molecular dynamics (3D) simulation of a polymer melt with 100 chains and 40 beads.