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Shear-Thinning in Oligomer Melts - Molecular Origins and Applications

Datta, Ranajay ; Yelash, Leonid ; Schmid, Friederike ; Kummer, Florian ; Oberlack, Martin ; Lukáčová-Medvid’ová, Mária ; Virnau, Peter (2023)
Shear-Thinning in Oligomer Melts - Molecular Origins and Applications.
In: Polymers, 2021, 13 (16)
doi: 10.26083/tuprints-00019574
Article, Secondary publication, Publisher's Version

Copyright Information: CC BY 4.0 International - Creative Commons, Attribution.

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Item Type: Article
Type of entry: Secondary publication
Title: Shear-Thinning in Oligomer Melts - Molecular Origins and Applications
Language: English
Date: 14 November 2023
Place of Publication: Darmstadt
Year of primary publication: 2021
Place of primary publication: Basel
Publisher: MDPI
Journal or Publication Title: Polymers
Volume of the journal: 13
Issue Number: 16
Collation: 20 Seiten
DOI: 10.26083/tuprints-00019574
Corresponding Links:
Origin: Secondary publication DeepGreen

We investigate the molecular origin of shear-thinning in melts of flexible, semiflexible and rigid oligomers with coarse-grained simulations of a sheared melt. Entanglements, alignment, stretching and tumbling modes or suppression of the latter all contribute to understanding how macroscopic flow properties emerge from the molecular level. In particular, we identify the rise and decline of entanglements with increasing chain stiffness as the major cause for the non-monotonic behaviour of the viscosity in equilibrium and at low shear rates, even for rather small oligomeric systems. At higher shear rates, chains align and disentangle, contributing to shear-thinning. By performing simulations of single chains in shear flow, we identify which of these phenomena are of collective nature and arise through interchain interactions and which are already present in dilute systems. Building upon these microscopic simulations, we identify by means of the Irving–Kirkwood formula the corresponding macroscopic stress tensor for a non-Newtonian polymer fluid. Shear-thinning effects in oligomer melts are also demonstrated by macroscopic simulations of channel flows. The latter have been obtained by the discontinuous Galerkin method approximating macroscopic polymer flows. Our study confirms the influence of microscopic details in the molecular structure of short polymers such as chain flexibility on macroscopic polymer flows.

Uncontrolled Keywords: shear flow, shear-thinning, semiflexible polymers, oligomers, heterogeneous multiscale methods, molecular dynamics, discontinuous Galerkin method, soft matter, non-Newtonian fluids
Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-195741
Additional Information:

This article belongs to the Special Issue Semiflexible Polymers II

Classification DDC: 500 Science and mathematics > 510 Mathematics
500 Science and mathematics > 530 Physics
600 Technology, medicine, applied sciences > 620 Engineering and machine engineering
Divisions: 16 Department of Mechanical Engineering > Fluid Dynamics (fdy)
Date Deposited: 14 Nov 2023 13:49
Last Modified: 17 Nov 2023 10:38
SWORD Depositor: Deep Green
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/19574
PPN: 513274480
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