dc.contributorUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:20:19Z
dc.date.available2014-05-20T15:20:19Z
dc.date.created2014-05-20T15:20:19Z
dc.date.issued2005-02-01
dc.identifierPhysica Status Solidi A-applied Research. Weinheim: Wiley-v C H Verlag Gmbh, v. 202, n. 3, p. 411-418, 2005.
dc.identifier0031-8965
dc.identifierhttp://hdl.handle.net/11449/31642
dc.identifier10.1002/pssa.200406929
dc.identifierWOS:000227725600017
dc.identifier3538107401166553
dc.description.abstractSmall-angle X-ray scattering (SAXS) and nitrogen adsorption techniques were used to study the temperature and time structural evolution of the nanoporosity in silica xerogels prepared from acid- and ultrasound-catalyzed hydrolysis of tetraetboxysilane (TEOS). Silica xerogels present a structure of nanopores of fully random shape, size, and distribution, which can be described by an exponential correlation function gamma(r) = exp (-r/a), where a is the correlation distance, as predicted by the Debye, Anderson, and Brumberger (DAB) model. The mean pore size was evaluated as about 1.25 nm from SAXS and about 1.9 nm from nitrogen adsorption. The nanopore elimination in TEOS sonohydrolysis-derived silica xerogels is readily accelerated at temperatures around 900 degrees C probably by the action of a viscous flow mechanism. The nanopore elimination process takes place in such a way that the pore volume fraction and the specific surface are reduced while the mean pore size remains constant. (c) 2005 WILEY-VCH Verlag GmbH S Co. KGaA, Weinheim.
dc.languageeng
dc.publisherWiley-Blackwell
dc.relationPhysica Status Solidi A: Applied Research
dc.rightsAcesso restrito
dc.sourceWeb of Science
dc.titleSmall-angle X-ray scattering and nitrogen adsorption study of the nanoporosity elimination in TEOS sonohydrolysis-derived xerogels
dc.typeArtículos de revistas


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