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Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant

The behaviour of confined lubricants at the atomic scale as affected by the interactions at the surface–lubricant interface is relevant in a range of technological applications in areas such as the automotive industry. In this paper, by performing fully atomistic molecular dynamics, we investigate t...

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Autores principales: Mathas, Dimitrios, Sarpa, Davide, Holweger, Walter, Wolf, Marcus, Bohnert, Christof, Bakolas, Vasilios, Procelewska, Joanna, Franke, Joerg, Rödel, Philipp, Skylaris, Chris-Kriton
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10660148/
https://www.ncbi.nlm.nih.gov/pubmed/38019999
http://dx.doi.org/10.1039/d3ra06929j
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author Mathas, Dimitrios
Sarpa, Davide
Holweger, Walter
Wolf, Marcus
Bohnert, Christof
Bakolas, Vasilios
Procelewska, Joanna
Franke, Joerg
Rödel, Philipp
Skylaris, Chris-Kriton
author_facet Mathas, Dimitrios
Sarpa, Davide
Holweger, Walter
Wolf, Marcus
Bohnert, Christof
Bakolas, Vasilios
Procelewska, Joanna
Franke, Joerg
Rödel, Philipp
Skylaris, Chris-Kriton
author_sort Mathas, Dimitrios
collection PubMed
description The behaviour of confined lubricants at the atomic scale as affected by the interactions at the surface–lubricant interface is relevant in a range of technological applications in areas such as the automotive industry. In this paper, by performing fully atomistic molecular dynamics, we investigate the regime where the viscosity starts to deviate from the bulk behaviour, a topic of great practical and scientific relevance. The simulations consist of setting up a shear flow by confining the lubricant between iron oxide surfaces. By using confined Non-Equilibrium Molecular Dynamics (NEMD) simulations at a pressure range of 0.1–1.0 GPa at 100 °C, we demonstrate that the film thickness of the fluid affects the behaviour of viscosity. We find that by increasing the number of lubricant molecules, we approach the viscosity value of the bulk fluid derived from previously published NEMD simulations for the same system. These changes in viscosity occurred at film thicknesses ranging from 10.12 to 55.93 Å. The viscosity deviations at different pressures between the system with the greatest number of lubricant molecules and the bulk simulations varied from −16% to 41%. The choice of the utilized force field for treating the atomic interactions was also investigated.
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spelling pubmed-106601482023-11-21 Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant Mathas, Dimitrios Sarpa, Davide Holweger, Walter Wolf, Marcus Bohnert, Christof Bakolas, Vasilios Procelewska, Joanna Franke, Joerg Rödel, Philipp Skylaris, Chris-Kriton RSC Adv Chemistry The behaviour of confined lubricants at the atomic scale as affected by the interactions at the surface–lubricant interface is relevant in a range of technological applications in areas such as the automotive industry. In this paper, by performing fully atomistic molecular dynamics, we investigate the regime where the viscosity starts to deviate from the bulk behaviour, a topic of great practical and scientific relevance. The simulations consist of setting up a shear flow by confining the lubricant between iron oxide surfaces. By using confined Non-Equilibrium Molecular Dynamics (NEMD) simulations at a pressure range of 0.1–1.0 GPa at 100 °C, we demonstrate that the film thickness of the fluid affects the behaviour of viscosity. We find that by increasing the number of lubricant molecules, we approach the viscosity value of the bulk fluid derived from previously published NEMD simulations for the same system. These changes in viscosity occurred at film thicknesses ranging from 10.12 to 55.93 Å. The viscosity deviations at different pressures between the system with the greatest number of lubricant molecules and the bulk simulations varied from −16% to 41%. The choice of the utilized force field for treating the atomic interactions was also investigated. The Royal Society of Chemistry 2023-11-21 /pmc/articles/PMC10660148/ /pubmed/38019999 http://dx.doi.org/10.1039/d3ra06929j Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/
spellingShingle Chemistry
Mathas, Dimitrios
Sarpa, Davide
Holweger, Walter
Wolf, Marcus
Bohnert, Christof
Bakolas, Vasilios
Procelewska, Joanna
Franke, Joerg
Rödel, Philipp
Skylaris, Chris-Kriton
Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant
title Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant
title_full Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant
title_fullStr Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant
title_full_unstemmed Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant
title_short Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – PAO-2 lubricant
title_sort calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite – pao-2 lubricant
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10660148/
https://www.ncbi.nlm.nih.gov/pubmed/38019999
http://dx.doi.org/10.1039/d3ra06929j
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