Surfactant self-assembly in the gas phase: bis(2-ethylhexyl)sulfosuccinate-alkaline metal ion aggregates.
The coating effect of alkali metal salt clusters by the surfactant anion bis(2-ethylhexyl)sulfosuccinate has been investigated by electrospray ionization mass spectrometry (MS) and MS/MS. The analysis of the data emphasized the formation and stability in the gas phase of reverse micelle-like surfactant aggregates carrying in their interior ionic clusters. Two main contributions have been postulated to account for the observed stability: intra-aggregate electrostatic interactions and screening of inter-aggregate attractive interactions due to the exclusion volume effect caused by the surfactant alkyl chains. Moreover, the stability and structural arrangement of these supramolecular aggregates result in strong dependency on the alkali metal salt identity.
Giorgi
Gianluca
G
Dipartimento di Chimica, Università degli Studi di Siena, Via Aldo Moro, I-53100 Siena, Italy. gianluca.giorgi@unisi.it
Ceraulo
Leopoldo
L
Liveri
Vincenzo Turco
VT
D005740:Gases / Q000737:chemistry; D008094:Lithium / Q000737:chemistry; D013058:Mass Spectrometry; D008670:Metals / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013386:Succinates / Q000737:chemistry*; D013501:Surface-Active Agents
D005740:Gases; D008670:Metals; D012996:Solutions; D013386:Succinates; D013501:Surface-Active Agents; C511925:bis(2-ethylhexyl)sulfosuccinate; D008094:Lithium; D012964:Sodium