Diffusivity and conductivity of a primitive model electrolyte in a nanopore

Yuk Wai Tang, I. Szalai, Kwong Yu Chan

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Equilibrium and non-equilibrium molecular dynamics simulations are applied to obtain the diffusion coefficient and electric conductivity of ions in dilute electrolytes confined in neutral cylindrical pores. The electrolyte is described with the restricted primitive model and the wall of the pore is modelled as a soft wall. The equilibrium molecular dynamics simulations show that the axial diffusion coefficient of ions decreases with increasing confinement. For a fixed pore radius the diffusion coefficient decreases with increasing number density of the ions. The current response of the system to an applied electric field is maintained at constant temperature by Gaussian isokinetic equations of motion, and at constant concentration by periodic boundary conditions with recycling of ions in the axial direction. The electric conductivity is calculated from the current density and the electric field applied for different pore sizes. In contrast to the trend in diffusivity, conductivity increases slightly in smaller pores. For a very small pore, however, conductivity is lower than the bulk, because oppositely charged ions moving in opposite directions under the electric field cannot avoid collisions with each other in a narrow channel.

Original languageEnglish
Pages (from-to)309-314
Number of pages6
JournalMolecular Physics
Volume99
Issue number4
DOIs
Publication statusPublished - Feb 20 2001

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Nanopores
Electrolytes
diffusivity
electrolytes
Ions
porosity
conductivity
Electric Conductivity
Electric fields
Molecular Dynamics Simulation
diffusion coefficient
Molecular dynamics
ions
electric fields
Thermal Conductivity
molecular dynamics
Computer simulation
Recycling
low conductivity
Pore size

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Diffusivity and conductivity of a primitive model electrolyte in a nanopore. / Tang, Yuk Wai; Szalai, I.; Chan, Kwong Yu.

In: Molecular Physics, Vol. 99, No. 4, 20.02.2001, p. 309-314.

Research output: Contribution to journalArticle

Tang, Yuk Wai ; Szalai, I. ; Chan, Kwong Yu. / Diffusivity and conductivity of a primitive model electrolyte in a nanopore. In: Molecular Physics. 2001 ; Vol. 99, No. 4. pp. 309-314.
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