Structural characteristics of silica sonogels prepared with different proportions of TEOS and TMOS
dc.contributor.author | Vollet, D. R. [UNESP] | |
dc.contributor.author | Nunes, L. M. [UNESP] | |
dc.contributor.author | Donatti, D. A. [UNESP] | |
dc.contributor.author | Ruiz, Alberto Ibanez [UNESP] | |
dc.contributor.author | Maceti, H. | |
dc.contributor.institution | Universidade Estadual Paulista (Unesp) | |
dc.contributor.institution | Ctr Univ Herminio Ometto Uniararas | |
dc.date.accessioned | 2013-09-30T18:50:50Z | |
dc.date.accessioned | 2014-05-20T14:16:35Z | |
dc.date.available | 2013-09-30T18:50:50Z | |
dc.date.available | 2014-05-20T14:16:35Z | |
dc.date.issued | 2008-03-01 | |
dc.description.abstract | Sonohydrolysis of mixtures of tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) with different TMOS/(TMOS + TEOS) molar ratio R was carried out to obtain similar to 2.0 x 10(-3) mol SiO2/cm(3) and similar to 86%-volume liquid phase wet gels. Aerogels were obtained by supercritical CO2 extraction in autoclave. The samples were analyzed by small-angle X-ray scattering (SAXS) and nitrogen adsorption. The structure of the wet gels can be described as a mass fractal structure with fractal dimension D similar to 2.2 and characteristic length increasing from similar to 4.6 nm for pure TEOS to similar to 6.4 nm for pure TMOS. A fraction of the porosity is eliminated with the supercritical process. The fundamental role of the TMOS/(TMOS + TEOS) molar ratio on the structure of the aerogels is to increase the porosity and the pore mean size as R changes from pure TEOS to pure TMOS. The supercritical process increases the mass fractal dimension and shortens the fractality domain in the mesopore region. A secondary structure appearing in the micropore region of the aerogels can be described as a mass/surface fractal structure with correlated mass fractal dimension D-m similar to 2.6 and surface fractal dimension D-s similar to 2.3. (C) 2007 Elsevier B.V. All rights reserved. | en |
dc.description.affiliation | Univ Estadual Paulista, IGCE, Dept Fis, BR-13500970 Rio Claro, SP, Brazil | |
dc.description.affiliation | Ctr Univ Herminio Ometto Uniararas, BR-13607339 Araras, SP, Brazil | |
dc.description.affiliationUnesp | Univ Estadual Paulista, IGCE, Dept Fis, BR-13500970 Rio Claro, SP, Brazil | |
dc.format.extent | 1467-1474 | |
dc.identifier | http://dx.doi.org/10.1016/j.jnoncrysol.2007.08.047 | |
dc.identifier.citation | Journal of Non-crystalline Solids. Amsterdam: Elsevier B.V., v. 354, n. 14, p. 1467-1474, 2008. | |
dc.identifier.doi | 10.1016/j.jnoncrysol.2007.08.047 | |
dc.identifier.issn | 0022-3093 | |
dc.identifier.lattes | 2661573794233385 | |
dc.identifier.lattes | 3538107401166553 | |
dc.identifier.lattes | 5890636096105376 | |
dc.identifier.uri | http://hdl.handle.net/11449/24985 | |
dc.identifier.wos | WOS:000253649700004 | |
dc.language.iso | eng | |
dc.publisher | Elsevier B.V. | |
dc.relation.ispartof | Journal of Non-Crystalline Solids | |
dc.relation.ispartofjcr | 2.488 | |
dc.relation.ispartofsjr | 0,722 | |
dc.rights.accessRights | Acesso restrito | |
dc.source | Web of Science | |
dc.subject | diffraction and scattering measurements | en |
dc.subject | porosity | en |
dc.subject | silica | en |
dc.subject | aerogels | en |
dc.subject | medium-range order | en |
dc.subject | adsorption | en |
dc.title | Structural characteristics of silica sonogels prepared with different proportions of TEOS and TMOS | en |
dc.type | Artigo | |
dcterms.license | http://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy | |
dcterms.rightsHolder | Elsevier B.V. | |
unesp.author.lattes | 2661573794233385 | |
unesp.author.lattes | 3538107401166553 | |
unesp.author.lattes | 5890636096105376 | |
unesp.author.orcid | 0000-0001-8154-9692[1] | |
unesp.campus | Universidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Rio Claro | pt |
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