Influence of Dispersity on the Relaxation of Entangled Polymers from Molecular Dynamics Simulations

Fuente: arXiv
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Main Authors: Tejuosho, Taofeek, Sampath, Janani
Format: Preprint
Published: 2025
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author Tejuosho, Taofeek
Sampath, Janani
author_facet Tejuosho, Taofeek
Sampath, Janani
contents Nonequilibrium molecular dynamics simulations are used to study the deformation behavior of disperse polymer melts by tracking test chains of length N = Mw, the weight average molecular weight, in melts of varying dispersity. At high strain rates, stress decreases with increasing dispersity up to the critical stretch ratio. After flow cessation, relaxation is anisotropic: the parallel component of the radius of gyration decreases monotonically with dispersity, but the perpendicular component exhibits non-monotonic behavior, with fast relaxation at low to intermediate stretching ratios, and slower relaxation at higher stretching ratios as dispersity increases. Single-chain structure factor shows a similar trend in the perpendicular direction, with fast relaxation at intermediate length scales in disperse systems, while the parallel component remains unaffected by dispersity. These findings reveal the complex, dispersity-dependent anisotropic relaxation mechanisms in moderately entangled polymer melts far from equilibrium.
format Preprint
id arxiv_https___arxiv_org_abs_2507_20935
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Influence of Dispersity on the Relaxation of Entangled Polymers from Molecular Dynamics Simulations
Tejuosho, Taofeek
Sampath, Janani
Soft Condensed Matter
Nonequilibrium molecular dynamics simulations are used to study the deformation behavior of disperse polymer melts by tracking test chains of length N = Mw, the weight average molecular weight, in melts of varying dispersity. At high strain rates, stress decreases with increasing dispersity up to the critical stretch ratio. After flow cessation, relaxation is anisotropic: the parallel component of the radius of gyration decreases monotonically with dispersity, but the perpendicular component exhibits non-monotonic behavior, with fast relaxation at low to intermediate stretching ratios, and slower relaxation at higher stretching ratios as dispersity increases. Single-chain structure factor shows a similar trend in the perpendicular direction, with fast relaxation at intermediate length scales in disperse systems, while the parallel component remains unaffected by dispersity. These findings reveal the complex, dispersity-dependent anisotropic relaxation mechanisms in moderately entangled polymer melts far from equilibrium.
title Influence of Dispersity on the Relaxation of Entangled Polymers from Molecular Dynamics Simulations
topic Soft Condensed Matter
url https://arxiv.org/abs/2507.20935