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Impact of Additive Hydrophilicity on Mixed Dye-Nonionic Surfactant Micelles : Micelle Morphology and Dye Localization

Müller, Wenke ; Sroka, Weronika ; Schweins, Ralf ; Nöcker, Bernd ; Poon, Jia Fei LU and Huber, Klaus (2024) In Langmuir
Abstract

The nonionic surfactant pentaethylene glycol-monododecylether C12E5 forms micelles in aqueous solutions with a lower critical solution temperature. This characteristic solution behavior of C12E5 is independent of the pH. Such micelles are used to solubilize a large variety of active guest molecules like for instance dyestuffs. An example is an acidic azo dye termed Blue used as a hair colorant. Depending on the pH, Blue gradually changes its hydrophilicity from the protonated BlueH at pH = 2 to the bivalent anion Blue2- at pH = 13 while keeping the shape and size of Blue essentially unchanged. These features of C12E5 and Blue offer the unique chance to... (More)

The nonionic surfactant pentaethylene glycol-monododecylether C12E5 forms micelles in aqueous solutions with a lower critical solution temperature. This characteristic solution behavior of C12E5 is independent of the pH. Such micelles are used to solubilize a large variety of active guest molecules like for instance dyestuffs. An example is an acidic azo dye termed Blue used as a hair colorant. Depending on the pH, Blue gradually changes its hydrophilicity from the protonated BlueH at pH = 2 to the bivalent anion Blue2- at pH = 13 while keeping the shape and size of Blue essentially unchanged. These features of C12E5 and Blue offer the unique chance to investigate the sole impact of a tunable hydrophilicity of a guest molecule on the solution behavior of mixed micelles of the guest and C12E5. Accordingly, the present work establishes a phase diagram of Blue-C12E5 micelles and analyzes their morphology including the spatial distribution of Blue in the micelles as a function of the hydrophilicity of Blue. Small angle neutron scattering reveals the size and shape of the micelles, and detailed contrast matching of the C12E5 supported by 1H NMR with NOESY provided insight into the localization of Blue within the micelles as its hydrophilicity changes.

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organization
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type
Contribution to journal
publication status
in press
subject
in
Langmuir
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:38640353
  • scopus:85191144474
ISSN
0743-7463
DOI
10.1021/acs.langmuir.4c00012
language
English
LU publication?
yes
id
06ef0c93-72bf-4e7c-9e29-ad195f793aba
date added to LUP
2024-05-07 11:05:20
date last changed
2024-05-07 11:06:08
@article{06ef0c93-72bf-4e7c-9e29-ad195f793aba,
  abstract     = {{<p>The nonionic surfactant pentaethylene glycol-monododecylether C<sub>12</sub>E<sub>5</sub> forms micelles in aqueous solutions with a lower critical solution temperature. This characteristic solution behavior of C<sub>12</sub>E<sub>5</sub> is independent of the pH. Such micelles are used to solubilize a large variety of active guest molecules like for instance dyestuffs. An example is an acidic azo dye termed Blue used as a hair colorant. Depending on the pH, Blue gradually changes its hydrophilicity from the protonated BlueH at pH = 2 to the bivalent anion Blue<sup>2-</sup> at pH = 13 while keeping the shape and size of Blue essentially unchanged. These features of C<sub>12</sub>E<sub>5</sub> and Blue offer the unique chance to investigate the sole impact of a tunable hydrophilicity of a guest molecule on the solution behavior of mixed micelles of the guest and C<sub>12</sub>E<sub>5</sub>. Accordingly, the present work establishes a phase diagram of Blue-C<sub>12</sub>E<sub>5</sub> micelles and analyzes their morphology including the spatial distribution of Blue in the micelles as a function of the hydrophilicity of Blue. Small angle neutron scattering reveals the size and shape of the micelles, and detailed contrast matching of the C<sub>12</sub>E<sub>5</sub> supported by <sup>1</sup>H NMR with NOESY provided insight into the localization of Blue within the micelles as its hydrophilicity changes.</p>}},
  author       = {{Müller, Wenke and Sroka, Weronika and Schweins, Ralf and Nöcker, Bernd and Poon, Jia Fei and Huber, Klaus}},
  issn         = {{0743-7463}},
  language     = {{eng}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Langmuir}},
  title        = {{Impact of Additive Hydrophilicity on Mixed Dye-Nonionic Surfactant Micelles : Micelle Morphology and Dye Localization}},
  url          = {{http://dx.doi.org/10.1021/acs.langmuir.4c00012}},
  doi          = {{10.1021/acs.langmuir.4c00012}},
  year         = {{2024}},
}