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On the stability of aqueous dispersions containing conducting colloidal particles.

Szparaga, Ryan LU ; Woodward, Clifford E and Forsman, Jan LU (2015) In Soft Matter 11(20). p.4011-4021
Abstract
We use a combination of simulations and a simple theoretical approach to investigate interactions between neutral conducting surfaces, immersed in an electrolyte solution. The study is conducted at the primitive model level, which necessitates the use of multiple image reflections. Our approximate theory is based on a classical density functional formulation of Poisson-Boltzmann theory. The same approach can in principle also be imported to more advanced treatments, where ion correlations are accounted for. An important limiting result that guides our treatment of the image forces, is that the repulsive salt-induced interactions cancel the attractive zero frequency van der Waals attraction at long range. That is, at vanishing frequency,... (More)
We use a combination of simulations and a simple theoretical approach to investigate interactions between neutral conducting surfaces, immersed in an electrolyte solution. The study is conducted at the primitive model level, which necessitates the use of multiple image reflections. Our approximate theory is based on a classical density functional formulation of Poisson-Boltzmann theory. The same approach can in principle also be imported to more advanced treatments, where ion correlations are accounted for. An important limiting result that guides our treatment of the image forces, is that the repulsive salt-induced interactions cancel the attractive zero frequency van der Waals attraction at long range. That is, at vanishing frequency, the van der Waals interaction between the conducting surfaces is, at large separations, perfectly screened by the intervening salt solution. The simulations are computationally intensive, due to a strong dependence upon the number of image reflections used, with especially poor convergence when an odd number of images is used. We demonstrate that our approximate density functional approach is remarkably accurate, even in the presence of a 2 : 1 salt, or when the surfaces preferentially adsorb one ion species. The former observation was rather unexpected, given the lack of ion correlations within our mean-field treatment, and is most likely due to a cancellation between two opposing effects, both of which are generated by ion correlations. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Soft Matter
volume
11
issue
20
pages
4011 - 4021
publisher
Royal Society of Chemistry
external identifiers
  • pmid:25899056
  • wos:000354449100008
  • scopus:84929377507
ISSN
1744-6848
DOI
10.1039/c5sm00161g
language
English
LU publication?
yes
id
2b4ed179-1a89-4627-9019-614845e28efc (old id 5341020)
date added to LUP
2015-04-30 12:08:09
date last changed
2017-07-05 17:33:14
@article{2b4ed179-1a89-4627-9019-614845e28efc,
  abstract     = {We use a combination of simulations and a simple theoretical approach to investigate interactions between neutral conducting surfaces, immersed in an electrolyte solution. The study is conducted at the primitive model level, which necessitates the use of multiple image reflections. Our approximate theory is based on a classical density functional formulation of Poisson-Boltzmann theory. The same approach can in principle also be imported to more advanced treatments, where ion correlations are accounted for. An important limiting result that guides our treatment of the image forces, is that the repulsive salt-induced interactions cancel the attractive zero frequency van der Waals attraction at long range. That is, at vanishing frequency, the van der Waals interaction between the conducting surfaces is, at large separations, perfectly screened by the intervening salt solution. The simulations are computationally intensive, due to a strong dependence upon the number of image reflections used, with especially poor convergence when an odd number of images is used. We demonstrate that our approximate density functional approach is remarkably accurate, even in the presence of a 2 : 1 salt, or when the surfaces preferentially adsorb one ion species. The former observation was rather unexpected, given the lack of ion correlations within our mean-field treatment, and is most likely due to a cancellation between two opposing effects, both of which are generated by ion correlations.},
  author       = {Szparaga, Ryan and Woodward, Clifford E and Forsman, Jan},
  issn         = {1744-6848},
  language     = {eng},
  number       = {20},
  pages        = {4011--4021},
  publisher    = {Royal Society of Chemistry},
  series       = {Soft Matter},
  title        = {On the stability of aqueous dispersions containing conducting colloidal particles.},
  url          = {http://dx.doi.org/10.1039/c5sm00161g},
  volume       = {11},
  year         = {2015},
}