Charge delocalization effects on Nafion structure and water /proton dynamics in hydrated environments

Rakesh Pant, Soumyadipta Sengupta, Alexey V. Lyulin (Corresponding author), Arun Venkatnathan (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

In this work, using molecular dynamics simulations, we examine the effect of atomic charge delocalization on the pendant side chain of Nafion membrane on the structural and dynamical properties in various hydrated environments. The sulfur-sulfur radial distribution functions suggest that the sulfonate groups of the pendant side chain have closer geometric proximity with an increase in charge delocalization. However, the interactions of the sulfonate groups with water molecules/hydronium ions show a slight change with the charge delocalization. The average water cluster size decreases significantly with charge delocalization, though the diffusion coefficients of water molecules (at medium and higher water concentration) increase initially and then decreases slightly with excessive charge delocalization. The diffusion coefficients of hydronium ions do not follow any particular trend with charge delocalization. A complex interplay between sulfur-sulfur, sulfur-water/hydronium interactions, and water cluster distribution plays an essential role in the magnitude of the diffusion coefficient of water molecules and hydronium ions.

LanguageEnglish
Article number112340
Number of pages6
JournalFluid Phase Equilibria
Volume504
DOIs
StatePublished - 15 Jan 2020

Fingerprint

Protons
Sulfur
hydronium ions
protons
Water
sulfur
water
diffusion coefficient
sulfonates
Molecules
Ions
molecules
perfluorosulfonic acid
radial distribution
Distribution functions
Molecular dynamics
proximity
distribution functions
interactions
molecular dynamics

Keywords

  • Charge delocalization
  • Cluster distribution
  • Diffusion coefficient
  • Molecular dynamics
  • Nafion

Cite this

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title = "Charge delocalization effects on Nafion structure and water /proton dynamics in hydrated environments",
abstract = "In this work, using molecular dynamics simulations, we examine the effect of atomic charge delocalization on the pendant side chain of Nafion membrane on the structural and dynamical properties in various hydrated environments. The sulfur-sulfur radial distribution functions suggest that the sulfonate groups of the pendant side chain have closer geometric proximity with an increase in charge delocalization. However, the interactions of the sulfonate groups with water molecules/hydronium ions show a slight change with the charge delocalization. The average water cluster size decreases significantly with charge delocalization, though the diffusion coefficients of water molecules (at medium and higher water concentration) increase initially and then decreases slightly with excessive charge delocalization. The diffusion coefficients of hydronium ions do not follow any particular trend with charge delocalization. A complex interplay between sulfur-sulfur, sulfur-water/hydronium interactions, and water cluster distribution plays an essential role in the magnitude of the diffusion coefficient of water molecules and hydronium ions.",
keywords = "Charge delocalization, Cluster distribution, Diffusion coefficient, Molecular dynamics, Nafion",
author = "Rakesh Pant and Soumyadipta Sengupta and Lyulin, {Alexey V.} and Arun Venkatnathan",
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language = "English",
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journal = "Fluid Phase Equilibria",
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Charge delocalization effects on Nafion structure and water /proton dynamics in hydrated environments. / Pant, Rakesh; Sengupta, Soumyadipta; Lyulin, Alexey V. (Corresponding author); Venkatnathan, Arun (Corresponding author).

In: Fluid Phase Equilibria, Vol. 504, 112340, 15.01.2020.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - Charge delocalization effects on Nafion structure and water /proton dynamics in hydrated environments

AU - Pant,Rakesh

AU - Sengupta,Soumyadipta

AU - Lyulin,Alexey V.

AU - Venkatnathan,Arun

PY - 2020/1/15

Y1 - 2020/1/15

N2 - In this work, using molecular dynamics simulations, we examine the effect of atomic charge delocalization on the pendant side chain of Nafion membrane on the structural and dynamical properties in various hydrated environments. The sulfur-sulfur radial distribution functions suggest that the sulfonate groups of the pendant side chain have closer geometric proximity with an increase in charge delocalization. However, the interactions of the sulfonate groups with water molecules/hydronium ions show a slight change with the charge delocalization. The average water cluster size decreases significantly with charge delocalization, though the diffusion coefficients of water molecules (at medium and higher water concentration) increase initially and then decreases slightly with excessive charge delocalization. The diffusion coefficients of hydronium ions do not follow any particular trend with charge delocalization. A complex interplay between sulfur-sulfur, sulfur-water/hydronium interactions, and water cluster distribution plays an essential role in the magnitude of the diffusion coefficient of water molecules and hydronium ions.

AB - In this work, using molecular dynamics simulations, we examine the effect of atomic charge delocalization on the pendant side chain of Nafion membrane on the structural and dynamical properties in various hydrated environments. The sulfur-sulfur radial distribution functions suggest that the sulfonate groups of the pendant side chain have closer geometric proximity with an increase in charge delocalization. However, the interactions of the sulfonate groups with water molecules/hydronium ions show a slight change with the charge delocalization. The average water cluster size decreases significantly with charge delocalization, though the diffusion coefficients of water molecules (at medium and higher water concentration) increase initially and then decreases slightly with excessive charge delocalization. The diffusion coefficients of hydronium ions do not follow any particular trend with charge delocalization. A complex interplay between sulfur-sulfur, sulfur-water/hydronium interactions, and water cluster distribution plays an essential role in the magnitude of the diffusion coefficient of water molecules and hydronium ions.

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