Structural characterization of frozen solutions of metal containing reverse micelles (Articolo in rivista)

Type
Label
  • Structural characterization of frozen solutions of metal containing reverse micelles (Articolo in rivista) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1021/la701974q (literal)
Alternative label
  • A.Longo, G.Portale, W.Bras, F.Giannici, A.Ruggirello, V.Turco Liveri (2007)
    Structural characterization of frozen solutions of metal containing reverse micelles
    in Langmuir
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • A.Longo, G.Portale, W.Bras, F.Giannici, A.Ruggirello, V.Turco Liveri (literal)
Pagina inizio
  • 11482 (literal)
Pagina fine
  • 11487 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 23 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • ISMN, Istituto per lo Studio dei Materiali Nanostrutturati, CNR, Via U. La Malfa 153, 90146 Palermo, Italy, Netherlands Organization for Scientific Research (NWO), 6 rue Jules Horowitz, BP220, 38043 Grenoble CEDEX, France, Dipartimento di Chimica Inorganica e Analitica \"Stanislao Cannizzaro\", UniVersita` di Palermo, Viale delle Scienze, Parco D'Orleans II, 90128, Palermo, Italy, and Dipartimento di Chimica Fisica \"Filippo Accascina\", UniVersita` di Palermo, Viale delle Scienze, Parco D'Orleans II, 90128 Palermo, Italy (literal)
Titolo
  • Structural characterization of frozen solutions of metal containing reverse micelles (literal)
Abstract
  • The microstructure of temperature-quenched solutions of reverse micelles formed by sodium, cobalt, ytterbium, and cobalt/ytterbium bis(2-ethylhexyl)sulfosuccinate in n-heptane has been investigated by SAXS and EXAFS. Some changes in the X-ray absorption spectra with respect to the same systems at room temperature have been observed. The analysis of the SAXS spectra leads to the hypothesis that at 77 K the closed spherical structure of reverse micelles is retained and that during the temperature quench they undergo a clustering process involving the transition from a quite random dispersion to the formation of more or less large clusters of strongly packed reverse micelles. This behavior is attributed to competitive effects caused by the temperature decrease. The prevalence of intermicellar attractive interactions with respect to Brownian motions leading to a collapse to more compact structure is in competition with the rapid decrease of reverse micelle diffusion rate involving a freezing of the local structures. In the case of cobalt, ytterbium, and cobalt/ytterbium bis(2-ethylhexyl)sulfosuccinate reverse micelles, further information from EXAFS measurements indicates that within the reverse micelle core exists a quite ordered nanosized domain composed of water, surfactant counterions, and oxygen atoms of the SO3- head groups. The conservation of local order and inverse structure during the clustering phenomenon that results from the fast freezing with liquid nitrogen of solutions of reverse micelles could have biological implications, i.e., the preservation of tissue samples at cryogenic temperatures. (literal)
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