title: A molecular dynamics study of structure, stability and fragmentation patterns of sodium bis(2-ethylhexyl)sulfosuccinate positively charged aggregates in vacuo.
abstract: Positively charged supramolecular aggregates formed in vacuo by n AOTNa (sodium bis(2-ethylhexyl)sulfosuccinate) molecules and n(c) additional sodium ions, i.e. [AOT(n)Na(n+n(c))](n(c)), have been investigated by molecular dynamics (MD) simulations for n = 1-20 and n(c) = 0-5. Statistical analysis of physical quantities like gyration radii, atomic B-factors and moment of inertia tensors provides detailed information on their structural and dynamical properties. Even for n(c) = 5, all stable aggregates show a reverse micelle-like structure with an internal solid-like core including sodium counterions and surfactant polar heads surrounded by an external layer consisting of the surfactant alkyl chains. Moreover, the aggregate shapes may be approximated by rather flat and elongated ellipsoids whose longer axis increases with n and n(c). The fragmentation patterns of a number of these aggregates have also been examined and have been found to markedly depend on the aggregate charge state. In one particular case, for which experimental findings are available in the literature, a good agreement is found with the present fragmentation data.
authors: Dipartimento di Scienze Biomediche e Biotecnologie, Universita` di Brescia, Viale Europa 11, 25123 Brescia, Italy. longhi@med.unibs.it
authors: Giovanna
authors: G
authors: Longhi
authors: Sergio
authors: S
authors: Abbate
authors: Leopoldo
authors: L
authors: Ceraulo
authors: Alberto
authors: A
authors: Ceselli
authors: Sandro L
authors: SL
authors: Fornili
authors: Vincenzo
authors: V
authors: Turco Liveri
mesh_terms: D004143:Dioctyl Sulfosuccinic Acid / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D013696:Temperature; D013816:Thermodynamics
chemical_list: D007477:Ions; D004143:Dioctyl Sulfosuccinic Acid