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Short range forces in surfactant systems. Specific ion-effects and ion competition

Söderman, Olle LU (2004) In Current Opinion in Colloid & Interface Science 9(1-2). p.154-157
Abstract
Electrostatic effects often dominate the behavior of charged surfactant systems. While descriptions on the level of the Poisson-Boltzmann equation are successful in describing many important features of such systems, they cannot predict those specific ion effects arising when changing counterions of the same valency and they often fail in predicting effects due to changing from a monovalent to a divalent counterion, everything else kept constant. We show in this communication two examples on how such specific ion effects are conveniently studied using equilibrium bulk surfactant systems. By systematically changing among alkali counterions in a lamellar liquid crystal while simultaneously measuring the NMR quadrupolar splitting of the ions,... (More)
Electrostatic effects often dominate the behavior of charged surfactant systems. While descriptions on the level of the Poisson-Boltzmann equation are successful in describing many important features of such systems, they cannot predict those specific ion effects arising when changing counterions of the same valency and they often fail in predicting effects due to changing from a monovalent to a divalent counterion, everything else kept constant. We show in this communication two examples on how such specific ion effects are conveniently studied using equilibrium bulk surfactant systems. By systematically changing among alkali counterions in a lamellar liquid crystal while simultaneously measuring the NMR quadrupolar splitting of the ions, ion competition may be investigated. The evolution of the microstructure (as determined with NMR diffusometry) in a microemulsion when changing from Br- to SO42- as counterions to a cationic twin-tailed surfactant constitutes a convenient tool to investigate effects due to changing in the charge of the counterion. Finally, based on a suggestion originally due to Wennerstrom, we suggest an explanation on the effects observed when a monovalent counter ion is replaced with a divalent one in surfactant systems; an explanation which is based on the concept of image charges. (C) 2004 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Surfactant systems, Ion-effects, Ion competition
in
Current Opinion in Colloid & Interface Science
volume
9
issue
1-2
pages
154 - 157
publisher
Elsevier
external identifiers
  • wos:000223973800026
  • scopus:4444319177
ISSN
1359-0294
DOI
10.1016/j.cocis.2004.05.021
language
English
LU publication?
yes
id
e2df3b76-c0f6-4c45-94ef-d665eaae52ec (old id 154086)
date added to LUP
2007-07-12 12:14:59
date last changed
2017-01-01 07:07:18
@article{e2df3b76-c0f6-4c45-94ef-d665eaae52ec,
  abstract     = {Electrostatic effects often dominate the behavior of charged surfactant systems. While descriptions on the level of the Poisson-Boltzmann equation are successful in describing many important features of such systems, they cannot predict those specific ion effects arising when changing counterions of the same valency and they often fail in predicting effects due to changing from a monovalent to a divalent counterion, everything else kept constant. We show in this communication two examples on how such specific ion effects are conveniently studied using equilibrium bulk surfactant systems. By systematically changing among alkali counterions in a lamellar liquid crystal while simultaneously measuring the NMR quadrupolar splitting of the ions, ion competition may be investigated. The evolution of the microstructure (as determined with NMR diffusometry) in a microemulsion when changing from Br- to SO42- as counterions to a cationic twin-tailed surfactant constitutes a convenient tool to investigate effects due to changing in the charge of the counterion. Finally, based on a suggestion originally due to Wennerstrom, we suggest an explanation on the effects observed when a monovalent counter ion is replaced with a divalent one in surfactant systems; an explanation which is based on the concept of image charges. (C) 2004 Elsevier Ltd. All rights reserved.},
  author       = {Söderman, Olle},
  issn         = {1359-0294},
  keyword      = {Surfactant systems,Ion-effects,Ion competition},
  language     = {eng},
  number       = {1-2},
  pages        = {154--157},
  publisher    = {Elsevier},
  series       = {Current Opinion in Colloid & Interface Science},
  title        = {Short range forces in surfactant systems. Specific ion-effects and ion competition},
  url          = {http://dx.doi.org/10.1016/j.cocis.2004.05.021},
  volume       = {9},
  year         = {2004},
}