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Interaction of octaethylene glycol n-dodecyl monoether with dioctadecyldimethylammonium bromide and chloride vesicles

Barreleiro, Paula LU ; Olofsson, Gerd LU ; Brown, W; Edwards, K; Bonassi, NM and Feitosa, E (2002) In Langmuir 18(4). p.1024-1029
Abstract
Several different methods were used to investigate the vesicle-to-micelle transition induced by the addition of the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) to spontaneously formed vesicle dispersions of dioctadecyldimethylammonium bromide and chloride (DODAX, X = Cl- and Br-). Dynamic light scattering reveals that fast mode micelles are formed upon addition of C12E6. The micellar mode becomes progressively dominant as the C12E8/DODAX molar ratio (R) is increased until the vesicle-to-micelle transition is complete. Turbidity, calorimetry, fluorescence quantum yield, and anisotropy measurements indicate two critical compositions: the first, R-sat, when the vesicle bilayer is saturated with C12E8 and the second,... (More)
Several different methods were used to investigate the vesicle-to-micelle transition induced by the addition of the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) to spontaneously formed vesicle dispersions of dioctadecyldimethylammonium bromide and chloride (DODAX, X = Cl- and Br-). Dynamic light scattering reveals that fast mode micelles are formed upon addition of C12E6. The micellar mode becomes progressively dominant as the C12E8/DODAX molar ratio (R) is increased until the vesicle-to-micelle transition is complete. Turbidity, calorimetry, fluorescence quantum yield, and anisotropy measurements indicate two critical compositions: the first, R-sat, when the vesicle bilayer is saturated with C12E8 and the second, R-sol, which corresponds to the complete vesicle-to-micelle transition. Below R-sat the vesicles swell due to incorporation of the surfactant into the vesicle bilayer, and above R-sat mixed micelles and bilayer structures coexist, The determined R-sat and R-sol range from 0 to 1 and 4 to 6, respectively, depending on the surfactant counterion and the experimental method used. Cryo-transmission electron microscopy micrographs show that when R approximate to 4, micelles coexist with extended bilayer fragments. In pure DODAX (1.0 mM) dispersions, unilamellar vesicles are observed. According to the DSC results, C12E8 lowers the gel-to-liquid crystalline transition temperature, T-m, of DODAX and broadens the main transition peak which disappears around R approximate to 5 and 6 for DODAC and DODAB, respectively. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
18
issue
4
pages
1024 - 1029
publisher
The American Chemical Society
external identifiers
  • wos:000174009300014
  • scopus:0037133453
ISSN
0743-7463
DOI
10.1021/la010876z
language
English
LU publication?
yes
id
8bcceb02-76d8-4188-ae85-8ee8660e2dba (old id 342769)
date added to LUP
2007-08-08 09:27:09
date last changed
2017-03-26 03:44:15
@article{8bcceb02-76d8-4188-ae85-8ee8660e2dba,
  abstract     = {Several different methods were used to investigate the vesicle-to-micelle transition induced by the addition of the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) to spontaneously formed vesicle dispersions of dioctadecyldimethylammonium bromide and chloride (DODAX, X = Cl- and Br-). Dynamic light scattering reveals that fast mode micelles are formed upon addition of C12E6. The micellar mode becomes progressively dominant as the C12E8/DODAX molar ratio (R) is increased until the vesicle-to-micelle transition is complete. Turbidity, calorimetry, fluorescence quantum yield, and anisotropy measurements indicate two critical compositions: the first, R-sat, when the vesicle bilayer is saturated with C12E8 and the second, R-sol, which corresponds to the complete vesicle-to-micelle transition. Below R-sat the vesicles swell due to incorporation of the surfactant into the vesicle bilayer, and above R-sat mixed micelles and bilayer structures coexist, The determined R-sat and R-sol range from 0 to 1 and 4 to 6, respectively, depending on the surfactant counterion and the experimental method used. Cryo-transmission electron microscopy micrographs show that when R approximate to 4, micelles coexist with extended bilayer fragments. In pure DODAX (1.0 mM) dispersions, unilamellar vesicles are observed. According to the DSC results, C12E8 lowers the gel-to-liquid crystalline transition temperature, T-m, of DODAX and broadens the main transition peak which disappears around R approximate to 5 and 6 for DODAC and DODAB, respectively.},
  author       = {Barreleiro, Paula and Olofsson, Gerd and Brown, W and Edwards, K and Bonassi, NM and Feitosa, E},
  issn         = {0743-7463},
  language     = {eng},
  number       = {4},
  pages        = {1024--1029},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Interaction of octaethylene glycol n-dodecyl monoether with dioctadecyldimethylammonium bromide and chloride vesicles},
  url          = {http://dx.doi.org/10.1021/la010876z},
  volume       = {18},
  year         = {2002},
}