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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
Artikel, Zweitveröffentlichung, Verlagsversion

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Kurzbeschreibung (Abstract)

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.

Typ des Eintrags: Artikel
Erschienen: 2023
Autor(en): Datta, Ranajay ; Yelash, Leonid ; Schmid, Friederike ; Kummer, Florian ; Oberlack, Martin ; Lukáčová-Medvid’ová, Mária ; Virnau, Peter
Art des Eintrags: Zweitveröffentlichung
Titel: Shear-Thinning in Oligomer Melts - Molecular Origins and Applications
Sprache: Englisch
Publikationsjahr: 14 November 2023
Ort: Darmstadt
Publikationsdatum der Erstveröffentlichung: 2021
Ort der Erstveröffentlichung: Basel
Verlag: MDPI
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Polymers
Jahrgang/Volume einer Zeitschrift: 13
(Heft-)Nummer: 16
Kollation: 20 Seiten
DOI: 10.26083/tuprints-00019574
URL / URN: https://tuprints.ulb.tu-darmstadt.de/19574
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Herkunft: Zweitveröffentlichung DeepGreen
Kurzbeschreibung (Abstract):

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.

Freie Schlagworte: shear flow, shear-thinning, semiflexible polymers, oligomers, heterogeneous multiscale methods, molecular dynamics, discontinuous Galerkin method, soft matter, non-Newtonian fluids
Status: Verlagsversion
URN: urn:nbn:de:tuda-tuprints-195741
Zusätzliche Informationen:

This article belongs to the Special Issue Semiflexible Polymers II

Sachgruppe der Dewey Dezimalklassifikatin (DDC): 500 Naturwissenschaften und Mathematik > 510 Mathematik
500 Naturwissenschaften und Mathematik > 530 Physik
600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau
Fachbereich(e)/-gebiet(e): 16 Fachbereich Maschinenbau
16 Fachbereich Maschinenbau > Fachgebiet für Strömungsdynamik (fdy)
Hinterlegungsdatum: 14 Nov 2023 13:49
Letzte Änderung: 15 Nov 2023 08:36
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