Counterion control of reactivity in anionic reverse micellar aggregates

Bardez, Élisabeth; Larrey, B.; Zhu, Xiaoyu; Valeur, Bernard

doi:10.1016/0009-2614(90)85378-p

Cited by 21 publications

(17 citation statements)

References 14 publications

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“…The aggregation of AOTNa in apolar solvents and the entrapment of guest molecules in its reverse micelles have been widely investigated not only for their theoretical significance, but also for the interesting applications of such supramolecular assemblies 5–18…”

Section: Methodsmentioning

confidence: 99%

Spatially ordered surfactant assemblies in the gas phase: negatively charged bis(2‐ethylhexyl)sulfosuccinate‐alkaline metal ion aggregates

Giorgi¹,

Giocaliere²,

Ceraulo̊³

et al. 2009

Rapid Comm Mass Spectrometry

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The formation and structural features of negatively charged aggregates of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) surfactant molecules in the gas phase have been investigated by electrospray ionization mass spectrometry (ESI-MS) and density functional theory calculations. Mainly driven by the interactions of alkali metal ions both with the oxygen atoms of the sulfonate group and with the succinate moiety of the AOT- anion, spatially ordered supramolecular assemblies, characterized by an internal core composed of surfactant counterions and hydrophilic head groups surrounded by the surfactant alkyl chains pointing outwards, are formed. Calculations have shown that surfactant self-organization in the gas phase is energetically favoured, the energy of formation of negatively charged aggregates from isolated AOTNa and AOT- being linearly related to the aggregation number. Information on the chelating properties of AOTNa towards clusters of inorganic salts was achieved by infusion of solutions at various AOTNa/metal salt (NaCl, NaBr, NaI, LiI, KCl, CsI, RbI) ratios in the ESI source of a mass spectrometer. A wide variety of negatively charged AOT-metal aggregates, some of them also incorporating halide (X-) ions, has been observed. Calculations have shown that the capture of a halide anion to give the AOTMX- species is favoured but the energetics of the process depends on the alkali metal and halide types. The use of energy-resolved mass spectrometry has allowed us to evaluate the stability of different complexes and to evaluate the role played by the metal ion. Overall, the present investigation supports the idea that, in the gas phase, mainly driven by electrostatic interactions, surfactant molecules are present as molecular aggregates characterized by a reverse micelle-like organization with an internal core formed by the surfactant counterions and head groups surrounded by the surfactant alkyl chains. These peculiar aggregates are able to incorporate ionic clusters in their hydrophilic core.

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Section: Methodsmentioning

confidence: 99%

Spatially ordered surfactant assemblies in the gas phase: negatively charged bis(2‐ethylhexyl)sulfosuccinate‐alkaline metal ion aggregates

Giorgi¹,

Giocaliere²,

Ceraulo̊³

et al. 2009

Rapid Comm Mass Spectrometry

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“…The aggregation process is fairly well characterized with respect to size and shape at various water contents (1)(2)(3)(4). All these works concluded that the micelle size and shape depend primarily on the water/surfactant molar concentration ratio, w 0 ϭ [H 2 …”

Section: Introductionmentioning

confidence: 98%

Effect of the Solvent on the Water Properties of Water/Oil Microemulsions

González-Blanco

Rodrı́guez

Velázquez

1999

Journal of Colloid and Interface Science

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“…This property has been exploited to enhance the solubility of species which should otherwise be insoluble, to protect them from the environment, to modulate their physicochemical properties and to investigate new and interesting applications. [5][6][7][8][9][10][11][12][13][14][15][16][17] The study of the role exerted by different aggregation modes on the interactions between protein and surfactants [18,19] and on protein refolding by reverse micelles has also attracted much interest. [20] Moreover, by simply exchanging the sodium counter ion of AOTwith other cations, specialized solubilizing properties can be conferred on the resulting supramolecular aggregates, such as enhanced luminescence of confined species, improved nanoparticle stability, and the formation of orientationally constrained counter ion-ligand complexes.…”

mentioning

confidence: 99%

Surfactant self‐assembling in the gas phase: bis(2‐ethylhexyl)‐sulfosuccinate divalent metal ion anionic aggregates

Giorgi

Ceraulo̊²,

Liveri

2012

Rapid Comm Mass Spectrometry

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This study shed some light on the assembling and chelating properties of AOT(-) towards divalent metal ions to form negatively charged assemblies, some of them incorporating the metal counter ion of the inorganic salt used. Differently from what was observed with positively charged AOT-M(II) aggregates, solvated species were not detectable. An exception to the even-electron rule was observed in the decomposition pathway of [AOTM(II)Cl(2)](-).

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Counterion control of reactivity in anionic reverse micellar aggregates

Cited by 21 publications

References 14 publications

Spatially ordered surfactant assemblies in the gas phase: negatively charged bis(2‐ethylhexyl)sulfosuccinate‐alkaline metal ion aggregates

Spatially ordered surfactant assemblies in the gas phase: negatively charged bis(2‐ethylhexyl)sulfosuccinate‐alkaline metal ion aggregates

Effect of the Solvent on the Water Properties of Water/Oil Microemulsions

Surfactant self‐assembling in the gas phase: bis(2‐ethylhexyl)‐sulfosuccinate divalent metal ion anionic aggregates

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