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Pulling polymers on energetically disordered surfaces: molecular dynamics tests of linear and non-linear response

Pulling polymers on energetically disordered surfaces: molecular dynamics tests of linear and non-linear response
Pulling polymers on energetically disordered surfaces: molecular dynamics tests of linear and non-linear response
We present equilibrium and non-equilibrium molecular dynamics simulations of flexible polymer chains absorbed on heterogeneous surfaces. The surfaces are flat but energetically disordered, as they consist of a random
mixture of weakly and more strongly absorbing sites (94% and 6%, respectively). For comparison, we have also simulated the two corresponding homogeneous surfaces. We find that this apparently weak energetic disorder can produce very significant changes of the chain statistics (expansion of the radii of gyration), equilibrium dynamics (reduction of the diffusion coeffcients) and non equilibrium response to a horizontal pulling force. On the disordered surfaces, the polymer-surface effective friction coefficient (ratio of pulling force and drift velocity) becomes strongly forcedependent,as the dominant mode of motion changes from localized stick-slip
events to smooth and continous sliding. This is strongly reminiscent of the Schallamach model of rubber friction and the Maier-Goritz picture of the Payne effect in filled elastomers.
elastomers, interfaces, molecular dynamics, non-equilibrium simulations, tribology
1022-1344
225-237
Raos, Guido
13d59cc1-061f-401c-9dc8-241b7d0299e2
Sluckin, Tim
8dbb6b08-7034-4ae2-aa65-6b80072202f6
Raos, Guido
13d59cc1-061f-401c-9dc8-241b7d0299e2
Sluckin, Tim
8dbb6b08-7034-4ae2-aa65-6b80072202f6

Raos, Guido and Sluckin, Tim (2013) Pulling polymers on energetically disordered surfaces: molecular dynamics tests of linear and non-linear response. Macromolecular Theory and Simulations, 22 (4), 225-237. (doi:10.1002/mats.201200075).

Record type: Article

Abstract

We present equilibrium and non-equilibrium molecular dynamics simulations of flexible polymer chains absorbed on heterogeneous surfaces. The surfaces are flat but energetically disordered, as they consist of a random
mixture of weakly and more strongly absorbing sites (94% and 6%, respectively). For comparison, we have also simulated the two corresponding homogeneous surfaces. We find that this apparently weak energetic disorder can produce very significant changes of the chain statistics (expansion of the radii of gyration), equilibrium dynamics (reduction of the diffusion coeffcients) and non equilibrium response to a horizontal pulling force. On the disordered surfaces, the polymer-surface effective friction coefficient (ratio of pulling force and drift velocity) becomes strongly forcedependent,as the dominant mode of motion changes from localized stick-slip
events to smooth and continous sliding. This is strongly reminiscent of the Schallamach model of rubber friction and the Maier-Goritz picture of the Payne effect in filled elastomers.

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More information

Published date: May 2013
Keywords: elastomers, interfaces, molecular dynamics, non-equilibrium simulations, tribology
Organisations: Mathematical Sciences

Identifiers

Local EPrints ID: 369788
URI: https://eprints.soton.ac.uk/id/eprint/369788
ISSN: 1022-1344
PURE UUID: 22ece88d-fce3-4c71-88ba-1bcec9704e1c
ORCID for Tim Sluckin: ORCID iD orcid.org/0000-0002-9163-0061

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Date deposited: 13 Oct 2014 10:30
Last modified: 06 Jun 2018 13:20

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