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Title: Reactive molecular dynamics simulations of an excess proton in polyethylene glycol-water solutions

Abstract

We investigate the effects of both triethylene glycol (TEG) and polyethylene glycol (PEG) on the structure and transport of an excess proton (H +) in aqueous solution. A new reactive force field (ReaxFF) parameterisation is carried out to better describe proton transfer of H + with PEG polymers in aqueous solution via training against density functional theory (DFT) calculations. Using this ReaxFF parameterisation, reactive molecular dynamics simulations are carried out for three different systems containing H +: bulk water, aqueous TEG, and aqueous PEG with a single, oriented polymer chain. The H + diffusivity is suppressed due to the presence of TEG and enhanced in the oriented chain PEG system, particularly along the axis parallel to the PEG chain, relative to bulk water. The enhancement in proton mobility along the chain axis is mainly due to the structural, rather than vehicular, component. From free energy calculations for H + transfer, the increase in proton mobility is not due to a reduction in activation energy. Finally, from pair distribution function analysis of the local structure for water and hydronium we hypothesise the increased mobility is due to an entropic effect, specifically a favourable hydrogen bond network for long range proton transportmore » due to the oriented PEG chain.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
  2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1546535
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Molecular Simulation
Additional Journal Information:
Journal Volume: 45; Journal Issue: 4-5; Journal ID: ISSN 0892-7022
Publisher:
Taylor & Francis
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 36 MATERIALS SCIENCE; proton transport; polyethylene glycol; water; ReaxFF

Citation Formats

McDonnell, Marshall T., and Keffer, David J. Reactive molecular dynamics simulations of an excess proton in polyethylene glycol-water solutions. United States: N. p., 2018. Web. doi:10.1080/08927022.2018.1557328.
McDonnell, Marshall T., & Keffer, David J. Reactive molecular dynamics simulations of an excess proton in polyethylene glycol-water solutions. United States. doi:10.1080/08927022.2018.1557328.
McDonnell, Marshall T., and Keffer, David J. Sun . "Reactive molecular dynamics simulations of an excess proton in polyethylene glycol-water solutions". United States. doi:10.1080/08927022.2018.1557328.
@article{osti_1546535,
title = {Reactive molecular dynamics simulations of an excess proton in polyethylene glycol-water solutions},
author = {McDonnell, Marshall T. and Keffer, David J.},
abstractNote = {We investigate the effects of both triethylene glycol (TEG) and polyethylene glycol (PEG) on the structure and transport of an excess proton (H+) in aqueous solution. A new reactive force field (ReaxFF) parameterisation is carried out to better describe proton transfer of H+ with PEG polymers in aqueous solution via training against density functional theory (DFT) calculations. Using this ReaxFF parameterisation, reactive molecular dynamics simulations are carried out for three different systems containing H+: bulk water, aqueous TEG, and aqueous PEG with a single, oriented polymer chain. The H+ diffusivity is suppressed due to the presence of TEG and enhanced in the oriented chain PEG system, particularly along the axis parallel to the PEG chain, relative to bulk water. The enhancement in proton mobility along the chain axis is mainly due to the structural, rather than vehicular, component. From free energy calculations for H+ transfer, the increase in proton mobility is not due to a reduction in activation energy. Finally, from pair distribution function analysis of the local structure for water and hydronium we hypothesise the increased mobility is due to an entropic effect, specifically a favourable hydrogen bond network for long range proton transport due to the oriented PEG chain.},
doi = {10.1080/08927022.2018.1557328},
journal = {Molecular Simulation},
number = 4-5,
volume = 45,
place = {United States},
year = {2018},
month = {8}
}

Journal Article:
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Works referenced in this record:

PEGylation, successful approach to drug delivery
journal, November 2005


NWChem: A comprehensive and scalable open-source solution for large scale molecular simulations
journal, September 2010

  • Valiev, M.; Bylaska, E. J.; Govind, N.
  • Computer Physics Communications, Vol. 181, Issue 9, p. 1477-1489
  • DOI: 10.1016/j.cpc.2010.04.018