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Equilibrium between poly(NN-dimethylacrylamide) and the lamellar phase of aerosol OT/water

Pacios, IE; Renamayor, CS; Horta, A; Lindman, Björn LU and Thuresson, Krister LU (2002) In The Journal of Physical Chemistry Part B 106(19). p.5035-5041
Abstract
A mixed amphiphilic system composed of the anionic surfactant Aerosol OT (AOT), in water forming a lamellar phase, to which is added a neutral noninteracting polymer, poly(N,N-dimethylacrylamide), is studied experimentally by SAXS, H-2 NMR, and microscopy, in a range of surfactant and polymer compositions. Addition of the polymer produces a decrease in the lamellar spacing, the decrease by the polymer being almost twice that produced by an equal volume of AOT. Microscopy reveals heterogeneity, but no macroscopic phase separation occurs. H-2 NMR detects that on increasing the polymer concentration some water is in an isotropic environment. It is inferred that the presence of the polymer induces a microscopic phase separation into a... (More)
A mixed amphiphilic system composed of the anionic surfactant Aerosol OT (AOT), in water forming a lamellar phase, to which is added a neutral noninteracting polymer, poly(N,N-dimethylacrylamide), is studied experimentally by SAXS, H-2 NMR, and microscopy, in a range of surfactant and polymer compositions. Addition of the polymer produces a decrease in the lamellar spacing, the decrease by the polymer being almost twice that produced by an equal volume of AOT. Microscopy reveals heterogeneity, but no macroscopic phase separation occurs. H-2 NMR detects that on increasing the polymer concentration some water is in an isotropic environment. It is inferred that the presence of the polymer induces a microscopic phase separation into a polymer-rich isotropic phase and a surfactant-rich lamellar phase, and this is tested theoretically by calculating the osmotic pressures in these two phases. In the lamellar phase, the effect of electrostatic, undulation, van der Waals, and hydration forces on the AOT bilayer is considered; in the isotropic phase, the osmotic contribution of the polymer is considered. These two pressures correlate well, supporting theoretically the hypothesis of the two phases in equilibrium. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
106
issue
19
pages
5035 - 5041
publisher
The American Chemical Society
external identifiers
  • wos:000175601100019
  • scopus:0037118380
ISSN
1520-5207
DOI
10.1021/jp025559v
language
English
LU publication?
yes
id
ac276329-abfa-4d74-8bbe-621faee3fe99 (old id 337528)
date added to LUP
2007-11-02 14:58:22
date last changed
2017-01-01 06:52:00
@article{ac276329-abfa-4d74-8bbe-621faee3fe99,
  abstract     = {A mixed amphiphilic system composed of the anionic surfactant Aerosol OT (AOT), in water forming a lamellar phase, to which is added a neutral noninteracting polymer, poly(N,N-dimethylacrylamide), is studied experimentally by SAXS, H-2 NMR, and microscopy, in a range of surfactant and polymer compositions. Addition of the polymer produces a decrease in the lamellar spacing, the decrease by the polymer being almost twice that produced by an equal volume of AOT. Microscopy reveals heterogeneity, but no macroscopic phase separation occurs. H-2 NMR detects that on increasing the polymer concentration some water is in an isotropic environment. It is inferred that the presence of the polymer induces a microscopic phase separation into a polymer-rich isotropic phase and a surfactant-rich lamellar phase, and this is tested theoretically by calculating the osmotic pressures in these two phases. In the lamellar phase, the effect of electrostatic, undulation, van der Waals, and hydration forces on the AOT bilayer is considered; in the isotropic phase, the osmotic contribution of the polymer is considered. These two pressures correlate well, supporting theoretically the hypothesis of the two phases in equilibrium.},
  author       = {Pacios, IE and Renamayor, CS and Horta, A and Lindman, Björn and Thuresson, Krister},
  issn         = {1520-5207},
  language     = {eng},
  number       = {19},
  pages        = {5035--5041},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Equilibrium between poly(NN-dimethylacrylamide) and the lamellar phase of aerosol OT/water},
  url          = {http://dx.doi.org/10.1021/jp025559v},
  volume       = {106},
  year         = {2002},
}