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Effects of the net charge on abundance and stability of supramolecular surfactant aggregates in gas phase
Author(s) -
Bongiorno David,
Ceraulo Leopoldo,
Giorgi Gianluca,
Indelicato Serena,
Ferrugia Mirella,
Ruggirello Angela,
Liveri Vincenzo Turco
Publication year - 2011
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1872
Subject(s) - chemistry , sulfonate , pulmonary surfactant , counterion , electrospray ionization , supramolecular chemistry , alkyl , amphiphile , sodium , molecule , ion , organic chemistry , polymer , biochemistry , copolymer
Self‐assembling of amphiphilic molecules under electrospray ionization (ESI) conditions is characterized by quite unexpected phenomenology. The noticeable differences with respect to the condensed phase are attributable to the absence of the surfactant‐solvent interactions, the presence of net charge in the aggregates, and the strong deviation from equilibrium conditions. Aiming to investigate the effects of the net charge on abundance and stability of supramolecular surfactant aggregates, positively and negatively charged aggregates of sodium bis(2‐ethylhexyl)sulfosuccinate (AOT) and sodium methane sulfonate (MetS), butane sulfonate (ButS) and octane sulfonate (OctS) have been studied by ESI mass spectrometry, energy resolved mass spectrometry and density functional theory calculations. The negatively charged aggregates are found to be less stable than their positive counterparts. The results are consistent with a self‐assembling pattern dominated by electrostatic interactions involving the counterions and head groups of the investigated amphiphilic compounds while the alkyl chains point outwards, protecting the aggregates from unlimited growth processes. Copyright © 2011 John Wiley & Sons, Ltd.