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Title: Coarse-grained modeling of polyethylene melts: Effect on dynamics

Abstract

The distinctive viscoelastic behavior of polymers results from a coupled interplay of motion on multiple length and time scales. Capturing the broad time and length scales of polymer motion remains a challenge. Using polyethylene (PE) as a model macromolecule, we construct coarse-grained (CG) models of PE with three to six methyl groups per CG bead and probe two critical aspects of the technique: pressure corrections required after iterative Boltzmann inversion (IBI) to generate CG potentials that match the pressure of reference fully atomistic melt simulations and the transferability of CG potentials across temperatures. While IBI produces nonbonded pair potentials that give excellent agreement between the atomistic and CG pair correlation functions, the resulting pressure for the CG models is large compared with the pressure of the atomistic system. We find that correcting the potential to match the reference pressure leads to nonbonded interactions with much deeper minima and slightly smaller effective bead diameter. However, simulations with potentials generated by IBI and pressure-corrected IBI result in similar mean-square displacements (MSDs) and stress autocorrelation functions G( t) for PE melts. While the time rescaling factor required to match CG and atomistic models is the same for pressure- and non-pressure-corrected CG models, itmore » strongly depends on temperature. Furthermore, transferability was investigated by comparing the MSDs and stress autocorrelation functions for potentials developed at different temperatures.« less

Authors:
 [1];  [2];  [3];  [4]; ORCiD logo [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. U.S. Naval Research Lab., Washington, D.C. (United States)
  3. Washington Univ., St. Louis, MO (United States)
  4. Clemson Univ., Clemson, SC (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1367349
Report Number(s):
SAND-2017-6200J
Journal ID: ISSN 1549-9618; 654461
Grant/Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Chemical Theory and Computation
Additional Journal Information:
Journal Volume: 13; Journal Issue: 6; Journal ID: ISSN 1549-9618
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE

Citation Formats

Peters, Brandon L., Salerno, K. Michael, Agrawal, Anupriya, Perahia, Dvora, and Grest, Gary S.. Coarse-grained modeling of polyethylene melts: Effect on dynamics. United States: N. p., 2017. Web. doi:10.1021/acs.jctc.7b00241.
Peters, Brandon L., Salerno, K. Michael, Agrawal, Anupriya, Perahia, Dvora, & Grest, Gary S.. Coarse-grained modeling of polyethylene melts: Effect on dynamics. United States. doi:10.1021/acs.jctc.7b00241.
Peters, Brandon L., Salerno, K. Michael, Agrawal, Anupriya, Perahia, Dvora, and Grest, Gary S.. Tue . "Coarse-grained modeling of polyethylene melts: Effect on dynamics". United States. doi:10.1021/acs.jctc.7b00241. https://www.osti.gov/servlets/purl/1367349.
@article{osti_1367349,
title = {Coarse-grained modeling of polyethylene melts: Effect on dynamics},
author = {Peters, Brandon L. and Salerno, K. Michael and Agrawal, Anupriya and Perahia, Dvora and Grest, Gary S.},
abstractNote = {The distinctive viscoelastic behavior of polymers results from a coupled interplay of motion on multiple length and time scales. Capturing the broad time and length scales of polymer motion remains a challenge. Using polyethylene (PE) as a model macromolecule, we construct coarse-grained (CG) models of PE with three to six methyl groups per CG bead and probe two critical aspects of the technique: pressure corrections required after iterative Boltzmann inversion (IBI) to generate CG potentials that match the pressure of reference fully atomistic melt simulations and the transferability of CG potentials across temperatures. While IBI produces nonbonded pair potentials that give excellent agreement between the atomistic and CG pair correlation functions, the resulting pressure for the CG models is large compared with the pressure of the atomistic system. We find that correcting the potential to match the reference pressure leads to nonbonded interactions with much deeper minima and slightly smaller effective bead diameter. However, simulations with potentials generated by IBI and pressure-corrected IBI result in similar mean-square displacements (MSDs) and stress autocorrelation functions G(t) for PE melts. While the time rescaling factor required to match CG and atomistic models is the same for pressure- and non-pressure-corrected CG models, it strongly depends on temperature. Furthermore, transferability was investigated by comparing the MSDs and stress autocorrelation functions for potentials developed at different temperatures.},
doi = {10.1021/acs.jctc.7b00241},
journal = {Journal of Chemical Theory and Computation},
number = 6,
volume = 13,
place = {United States},
year = {Tue May 23 00:00:00 EDT 2017},
month = {Tue May 23 00:00:00 EDT 2017}
}

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