Ab initio molecular dynamics simulation of proton hopping in a model polymer membrane

Ram Devanathan, Nagesh Idupulapati, Marcel D. Baer, Christopher J. Mundy, Michel Dupuis

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

We report the results of ab initio molecular dynamics simulations of a model Nafion polymer membrane initially equilibrated using classical molecular dynamics simulations. We studied three hydration levels (λ) of 3, 9, and 15 H2O/SO3 - corresponding to dry, hydrated, and saturated fuel cell membrane, respectively. The barrier for proton transfer from the SO3 --H3O+ contact ion pair to a solvent-separated ion pair decreased from 2.3 kcal/mol for λ = 3 to 0.8 kcal/mol for λ = 15. The barrier for proton transfer between two water molecules was in the range from 0.7 to 0.8 kcal/mol for the λ values studied. The number of proton shuttling events between a pair of water molecules is an order of magnitude more than the number of proton hops across three distinct water molecules. The proton diffusion coefficient at λ = 15 is about 0.9 × 10-5 cm2/s, which is in good agreement with experiment and our previous quantum hopping molecular dynamics simulations.

Original languageEnglish
Pages (from-to)16522-16529
Number of pages8
JournalJournal of Physical Chemistry B
Volume117
Issue number51
DOIs
Publication statusPublished - Dec 27 2013

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Molecular dynamics
Protons
Polymers
Proton transfer
molecular dynamics
membranes
Membranes
Molecules
protons
Water
Computer simulation
polymers
Ions
simulation
Cell membranes
Hydration
Fuel cells
water
molecules
fuel cells

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Ab initio molecular dynamics simulation of proton hopping in a model polymer membrane. / Devanathan, Ram; Idupulapati, Nagesh; Baer, Marcel D.; Mundy, Christopher J.; Dupuis, Michel.

In: Journal of Physical Chemistry B, Vol. 117, No. 51, 27.12.2013, p. 16522-16529.

Research output: Contribution to journalArticle

Devanathan, Ram ; Idupulapati, Nagesh ; Baer, Marcel D. ; Mundy, Christopher J. ; Dupuis, Michel. / Ab initio molecular dynamics simulation of proton hopping in a model polymer membrane. In: Journal of Physical Chemistry B. 2013 ; Vol. 117, No. 51. pp. 16522-16529.
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