Role of the surface state and structural feature in the thermoreversible sol-gel transition of a zirconyl aqueous precursor modified by sulfuric acid

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dc.contributor.authorChiavacci, L. A.
dc.contributor.authorSantilli, Celso Valentim [UNESP]
dc.contributor.authorPulcinelli, Sandra Helena [UNESP]
dc.contributor.authorBourgaux, C.
dc.contributor.authorBriois, V
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniv Paris 11
dc.date.accessioned2014-05-20T15:27:13Z
dc.date.available2014-05-20T15:27:13Z
dc.date.issued2004-10-19
dc.description.abstractThe sols produced by admixture of ZrOCl2 acidified solutions to hot H2SO4 aqueous solutions were studied to clarify the effects of Cl- and SO42- ions on the kinetic stability of nanoparticles and to obtain some new evidence concerning the mechanism of a thermoreversible sol-gel transition observed in this system. The study of suspensions prepared with different molar ratios R-S = [Zr]/[SO42-] and R-Cl = [Zr]/[Cl-] revealed domains of composition of formation of thermoreversible gels, thermostable sols, and powder precipitation. The effects of R-S and R-Cl on the structural features of nanoparticles and on the particle solution interface were systematically analyzed for samples of thermoreversible and thermostable sol domains. Small-angle X-ray scattering measurements revealed the presence of small fractal aggregates in all samples of thermoreversible domains, while compact packing aggregates of primary particles are present in the thermostable sol. Extended X-ray absorption fine structure and elemental chemical analysis revealed that irrespective of the nominal value of R-S and R-Cl all studied samples of the thermoreversible domain are constituted by a well-defined compound possessing an inner core made of hydroxyl and oxo groups bridging together zirconium atoms surrounded on the surface by complexing sulfate ligands. zeta potentials of powders extracted by freeze-drying from the thermoreversible gel revealed a point of surface charge inversion attributed to the specific adsorption of SO42- ion. Thermoreversible gel formation is rationalized by considering the effect of the specific adsorption on the electrical double-layer repulsion together with the temperature dependency of the physical chemical properties of ions in solution.en
dc.description.affiliationUNESP, Inst Chem, BR-14801970 Araraquara, SP, Brazil
dc.description.affiliationUniv Paris 11, LURE, F-91898 Orsay, France
dc.description.affiliationUnespUNESP, Inst Chem, BR-14801970 Araraquara, SP, Brazil
dc.format.extent3995-4004
dc.identifierhttp://dx.doi.org/10.1021/cm035258d
dc.identifier.citationChemistry of Materials. Washington: Amer Chemical Soc, v. 16, n. 21, p. 3995-4004, 2004.
dc.identifier.doi10.1021/cm035258d
dc.identifier.issn0897-4756
dc.identifier.lattes5584298681870865
dc.identifier.lattes9971202585286967
dc.identifier.orcid0000-0002-8356-8093
dc.identifier.urihttp://hdl.handle.net/11449/37241
dc.identifier.wosWOS:000224541600007
dc.language.isoeng
dc.publisherAmer Chemical Soc
dc.relation.ispartofChemistry of Materials
dc.relation.ispartofjcr9.890
dc.relation.ispartofsjr4,675
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.titleRole of the surface state and structural feature in the thermoreversible sol-gel transition of a zirconyl aqueous precursor modified by sulfuric aciden
dc.typeArtigo
dcterms.licensehttp://pubs.acs.org/paragonplus/copyright/jpa_form_a.pdf
dcterms.rightsHolderAmer Chemical Soc
unesp.author.lattes9971202585286967
unesp.author.lattes5584298681870865[2]
unesp.author.orcid0000-0002-8356-8093[2]
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Química, Araraquarapt

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