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Attraction between neutral dielectrics mediated by multivalent ions in an asymmetric ionic fluid

Kanduc, Matej; Naji, Ali; Forsman, Jan LU and Podgornik, Rudolf (2012) In Journal of Chemical Physics 137(17).
Abstract
We study the interaction between two neutral plane-parallel dielectric bodies in the presence of a highly asymmetric ionic fluid, containing multivalent as well as monovalent (salt) ions. Image charge interactions, due to dielectric discontinuities at the boundaries, as well as effects from ion confinement in the slit region between the surfaces are taken fully into account, leading to image-generated depletion attraction, ion correlation attraction, and steric-like repulsive interactions. We investigate these effects by employing a combination of Monte Carlo simulation methods, including explicit-ion simulations (where all electrostatic interactions are simulated explicitly) and implicit-ion simulations (where monovalent ions are replaced... (More)
We study the interaction between two neutral plane-parallel dielectric bodies in the presence of a highly asymmetric ionic fluid, containing multivalent as well as monovalent (salt) ions. Image charge interactions, due to dielectric discontinuities at the boundaries, as well as effects from ion confinement in the slit region between the surfaces are taken fully into account, leading to image-generated depletion attraction, ion correlation attraction, and steric-like repulsive interactions. We investigate these effects by employing a combination of Monte Carlo simulation methods, including explicit-ion simulations (where all electrostatic interactions are simulated explicitly) and implicit-ion simulations (where monovalent ions are replaced by an effective screened electrostatic potential between multivalent ions), as well as an approximate analytical theory. The latter incorporates strong ion-image charge correlations, which develop in the presence of high valency ions in the mixture. We show that the implicit-ion simulations and the proposed analytical theory can describe the explicit simulation results on a qualitative level, while excellent quantitative agreement can be obtained for sufficiently large monovalent salt concentrations. The resultant attractive interaction between the neutral surfaces is shown to be significant, as compared with the usual van der Waals interactions between semi-infinite dielectrics, and can thus play an important role at the nano scale. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4763472] (Less)
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organization
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type
Contribution to journal
publication status
published
subject
keywords
dielectric liquids, Monte Carlo methods, permittivity
in
Journal of Chemical Physics
volume
137
issue
17
publisher
American Institute of Physics
external identifiers
  • wos:000310854000032
  • scopus:84868674673
ISSN
0021-9606
DOI
10.1063/1.4763472
language
English
LU publication?
yes
id
367609b6-aae3-4d09-a615-1ea9bdf69eb1 (old id 3388256)
date added to LUP
2013-01-30 14:15:47
date last changed
2017-10-01 03:14:20
@article{367609b6-aae3-4d09-a615-1ea9bdf69eb1,
  abstract     = {We study the interaction between two neutral plane-parallel dielectric bodies in the presence of a highly asymmetric ionic fluid, containing multivalent as well as monovalent (salt) ions. Image charge interactions, due to dielectric discontinuities at the boundaries, as well as effects from ion confinement in the slit region between the surfaces are taken fully into account, leading to image-generated depletion attraction, ion correlation attraction, and steric-like repulsive interactions. We investigate these effects by employing a combination of Monte Carlo simulation methods, including explicit-ion simulations (where all electrostatic interactions are simulated explicitly) and implicit-ion simulations (where monovalent ions are replaced by an effective screened electrostatic potential between multivalent ions), as well as an approximate analytical theory. The latter incorporates strong ion-image charge correlations, which develop in the presence of high valency ions in the mixture. We show that the implicit-ion simulations and the proposed analytical theory can describe the explicit simulation results on a qualitative level, while excellent quantitative agreement can be obtained for sufficiently large monovalent salt concentrations. The resultant attractive interaction between the neutral surfaces is shown to be significant, as compared with the usual van der Waals interactions between semi-infinite dielectrics, and can thus play an important role at the nano scale. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4763472]},
  articleno    = {174704},
  author       = {Kanduc, Matej and Naji, Ali and Forsman, Jan and Podgornik, Rudolf},
  issn         = {0021-9606},
  keyword      = {dielectric liquids,Monte Carlo methods,permittivity},
  language     = {eng},
  number       = {17},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Attraction between neutral dielectrics mediated by multivalent ions in an asymmetric ionic fluid},
  url          = {http://dx.doi.org/10.1063/1.4763472},
  volume       = {137},
  year         = {2012},
}