Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study
We have performed coarse-grained molecular-dynamics simulations on both flexible and semiflexible multi-bead-spring model polymer brushes in the presence of explicit solvent particles, to explore their tribological and structural behaviors. The effect of stiffness and tethering density on equilibriu...
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| Format: | Article |
| Language: | English |
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MDPI AG
2016-07-01
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| Series: | Polymers |
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| Online Access: | http://www.mdpi.com/2073-4360/8/7/254 |
| _version_ | 1811218660124000256 |
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| author | Manjesh K. Singh Patrick Ilg Rosa M. Espinosa-Marzal Nicholas D. Spencer Martin Kröger |
| author_facet | Manjesh K. Singh Patrick Ilg Rosa M. Espinosa-Marzal Nicholas D. Spencer Martin Kröger |
| author_sort | Manjesh K. Singh |
| collection | DOAJ |
| description | We have performed coarse-grained molecular-dynamics simulations on both flexible and semiflexible multi-bead-spring model polymer brushes in the presence of explicit solvent particles, to explore their tribological and structural behaviors. The effect of stiffness and tethering density on equilibrium-brush height is seen to be well reproduced within a Flory-type theory. After discussing the equilibrium behavior of the model brushes, we first study the shearing behavior of flexible chains at different grafting densities covering brush and mushroom regimes. Next, we focus on the effect of chain stiffness on the tribological behavior of polymer brushes. The tribological properties are interpreted by means of the simultaneously recorded density profiles. We find that the friction coefficient decreases with increasing persistence length, both in velocity and separation-dependency studies, over the stiffness range explored in this work. |
| first_indexed | 2024-04-12T07:13:07Z |
| format | Article |
| id | doaj.art-c4da538144c44db4bb3f34c5727533b5 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-04-12T07:13:07Z |
| publishDate | 2016-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-c4da538144c44db4bb3f34c5727533b52022-12-22T03:42:34ZengMDPI AGPolymers2073-43602016-07-018725410.3390/polym8070254polym8070254Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics StudyManjesh K. Singh0Patrick Ilg1Rosa M. Espinosa-Marzal2Nicholas D. Spencer3Martin Kröger4Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, SwitzerlandSchool of Mathematical and Physical Sciences, University of Reading, Reading RG6 6AX, UKLaboratory for Smart Interfaces in Environmental Nanotechnology, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USALaboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, SwitzerlandPolymer Physics, Department of Materials, ETH Zurich, CH–8093 Zurich, SwitzerlandWe have performed coarse-grained molecular-dynamics simulations on both flexible and semiflexible multi-bead-spring model polymer brushes in the presence of explicit solvent particles, to explore their tribological and structural behaviors. The effect of stiffness and tethering density on equilibrium-brush height is seen to be well reproduced within a Flory-type theory. After discussing the equilibrium behavior of the model brushes, we first study the shearing behavior of flexible chains at different grafting densities covering brush and mushroom regimes. Next, we focus on the effect of chain stiffness on the tribological behavior of polymer brushes. The tribological properties are interpreted by means of the simultaneously recorded density profiles. We find that the friction coefficient decreases with increasing persistence length, both in velocity and separation-dependency studies, over the stiffness range explored in this work.http://www.mdpi.com/2073-4360/8/7/254boundary lubricationshearcoefficient of frictionsolvent qualitysemiflexible polymersplanar brushbending stiffnessFENE-chain modelpolymer brushes |
| spellingShingle | Manjesh K. Singh Patrick Ilg Rosa M. Espinosa-Marzal Nicholas D. Spencer Martin Kröger Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study Polymers boundary lubrication shear coefficient of friction solvent quality semiflexible polymers planar brush bending stiffness FENE-chain model polymer brushes |
| title | Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study |
| title_full | Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study |
| title_fullStr | Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study |
| title_full_unstemmed | Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study |
| title_short | Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study |
| title_sort | influence of chain stiffness grafting density and normal load on the tribological and structural behavior of polymer brushes a nonequilibrium molecular dynamics study |
| topic | boundary lubrication shear coefficient of friction solvent quality semiflexible polymers planar brush bending stiffness FENE-chain model polymer brushes |
| url | http://www.mdpi.com/2073-4360/8/7/254 |
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