The capability of infrared multiple photon dissociation(IRMPD) spectroscopy to gain structural information on surfactant-basedsupramolecular aggregates has been exploited to elucidate intermolecularinteractions and local organization of positively charged sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) aggregates in the gas phase. A detailed analysisof the stretching modes of theAOTNaCOand SO3- head groups allows one todirectly probe their interactions with sodium counterions and to gain insight intheir organization within the aggregate. Similarities and differences of theIRMPD spectra as compared to the infrared absorption spectrum of micellizedAOTNa in CCl4 have been analyzed. They strongly suggest a reverse micellelikeorganization of AOTNa charged aggregates in the gas phase. Apart fromlow-abundance fragmentation channels of the AOTNa (molecule) itself, themain dissociation pathway of singly charged surfactant aggregates is the loss of neutral surfactant molecules, while doubly chargedaggregates dissociate preferentially by charge separation forming singly charged species. In both cases, decomposition leads to theformation of the most energetically stable charged fragments.
|Numero di pagine||5|
|Rivista||JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL|
|Stato di pubblicazione||Published - 2011|
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