Entanglements in Quiescent and Sheared Polymer Melts

Abstract

We visualize entanglements in polymer melts using molecular dynamics simulation. A bead at an entanglement interacts persistently for long times with the non-bonded beads (those excluding the adjacent ones in the same chain). The interaction energy of each bead with the non-bonded beads is averaged over a time interval $\tau$ much longer than microscopic times but shorter than the onset time of tube constraints ${\tau }_{\mathrm{e}}$. Entanglements can then be detected as hot spots consisting of several beads with relatively large values of the time-averaged interaction energy. We next apply a shear flow with rate much faster than the entangle motion. With increasing strain the chains take zigzag shapes and a half of the hot spots become bent. The chains are first stretched as a network but, as the bends approach the chain ends, disentanglements subsequently occur, leading to stress overshoot observed experimentally.

arXiv comment19 pages, 11 figures

References in corpus (4)

• What is the Entanglement Length in a Polymer Melt ?
• Dynamics and Rheology of a Supercooled Polymer Melt in Shear Flow
• Short Time Behavior in De Gennes' Reptation Model
• Individual Entanglements in a Simulated Polymer Melt

Cited by in corpus (5)

• Stress overshoot in a simple yield stress fluid: an extensive study combining rheology and velocimetry
• Multi-chain Slip-spring Model for Entangled Polymer Dynamics
• Microscopic Description of Entanglements in Polyethylene Networks and Melts: Strong, Weak, Pairwise, and Collective Attributes
• Dynamic surface decoupling in a sheared polymer melt
• Spatial correlations of entangled polymer dynamics