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Fusion and fission of fluid amphiphilic bilayers

Gotter, M; Strey, R; Olsson, Ulf LU and Wennerström, Håkan LU (2005) In Faraday Discussions 129. p.327-338
Abstract
The system water-oil (n-decane)-nonionic surfactant (C12E5) forms bilayer phases in a large concentration region, but, for a given oil-to-surfactant ratio, only in a narrow temperature range. In addition to the anisotropic lamellar phase (L-alpha) there is also, at slightly higher temperature, a sponge or L-3-phase where the bilayers build up an isotropic structure extending macroscopically in three dimensions. In this phase the bilayer mid-surface has a mean curvature close to zero and a negative Euler characteristic. In this paper we study how the bilayers in the lamellar and the sponge phase respond dynamically to sudden temperature changes. The monolayer spontaneous curvature depends sensitively on temperature and a change of... (More)
The system water-oil (n-decane)-nonionic surfactant (C12E5) forms bilayer phases in a large concentration region, but, for a given oil-to-surfactant ratio, only in a narrow temperature range. In addition to the anisotropic lamellar phase (L-alpha) there is also, at slightly higher temperature, a sponge or L-3-phase where the bilayers build up an isotropic structure extending macroscopically in three dimensions. In this phase the bilayer mid-surface has a mean curvature close to zero and a negative Euler characteristic. In this paper we study how the bilayers in the lamellar and the sponge phase respond dynamically to sudden temperature changes. The monolayer spontaneous curvature depends sensitively on temperature and a change of temperature thus provides a driving force for a change in bilayer topology. The equilibration therefore involves kinetic steps of fusion/fission of bilayers. Such dynamic processes have previously been monitored by temperature jump experiments using light scattering in the sponge phase. These experiments revealed an extraordinarily strong dependence of the relaxation time on the bilayer volume fraction phi. At phi<0.1 the relaxation times are so slow that experiments using deuterium nuclear magnetic resonance (H-2-NMR) appear feasible. We here report on the first experiments concerned with the dynamics of the macroscopic phase transition sponge-lamellae by H-2-NMR. We find that the sponge-to-lamellae transition occurs through a nucleation process followed by domain growth involving bilayer fission at domain boundaries. In contrast, the lamellae-to-sponge transformation apparently occurs through a succession of uncorrelated bilayer fusion events. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Faraday Discussions
volume
129
pages
327 - 338
publisher
Royal Society of Chemistry
external identifiers
  • wos:000225786100025
  • pmid:15715316
  • scopus:13244276400
ISSN
1364-5498
DOI
10.1039/b405363j
language
English
LU publication?
yes
id
c5e008b6-0e8c-49a7-ab88-9d3cd9f8a457 (old id 157384)
date added to LUP
2007-07-11 12:04:37
date last changed
2017-01-01 04:21:01
@article{c5e008b6-0e8c-49a7-ab88-9d3cd9f8a457,
  abstract     = {The system water-oil (n-decane)-nonionic surfactant (C12E5) forms bilayer phases in a large concentration region, but, for a given oil-to-surfactant ratio, only in a narrow temperature range. In addition to the anisotropic lamellar phase (L-alpha) there is also, at slightly higher temperature, a sponge or L-3-phase where the bilayers build up an isotropic structure extending macroscopically in three dimensions. In this phase the bilayer mid-surface has a mean curvature close to zero and a negative Euler characteristic. In this paper we study how the bilayers in the lamellar and the sponge phase respond dynamically to sudden temperature changes. The monolayer spontaneous curvature depends sensitively on temperature and a change of temperature thus provides a driving force for a change in bilayer topology. The equilibration therefore involves kinetic steps of fusion/fission of bilayers. Such dynamic processes have previously been monitored by temperature jump experiments using light scattering in the sponge phase. These experiments revealed an extraordinarily strong dependence of the relaxation time on the bilayer volume fraction phi. At phi&lt;0.1 the relaxation times are so slow that experiments using deuterium nuclear magnetic resonance (H-2-NMR) appear feasible. We here report on the first experiments concerned with the dynamics of the macroscopic phase transition sponge-lamellae by H-2-NMR. We find that the sponge-to-lamellae transition occurs through a nucleation process followed by domain growth involving bilayer fission at domain boundaries. In contrast, the lamellae-to-sponge transformation apparently occurs through a succession of uncorrelated bilayer fusion events.},
  author       = {Gotter, M and Strey, R and Olsson, Ulf and Wennerström, Håkan},
  issn         = {1364-5498},
  language     = {eng},
  pages        = {327--338},
  publisher    = {Royal Society of Chemistry},
  series       = {Faraday Discussions},
  title        = {Fusion and fission of fluid amphiphilic bilayers},
  url          = {http://dx.doi.org/10.1039/b405363j},
  volume       = {129},
  year         = {2005},
}