Please use this identifier to cite or link to this item:
Full metadata record
DC FieldValueLanguage
dc.typeArtigo de periódicopt
dc.titleMicellization Of Ctab In The Presence Of Silicate Anions And The Exchange Between Bromide And Silicate At The Micelle Surface: A Step To Understand The Formation Of Mesoporous Molecular Sieves At Extremely Low Surfactant And Silicate
dc.contributor.authorVautier-Giongo, Carolinapt
dc.contributor.authorPastore, Heloise Opt
unicamp.authorCarolina Vautier-Giongo, Micro- and Mesoporous Molecular Sieves Group, Instituto de Química, Universidade Estadual de Campinas, CP 6154, CEP, 13083-970 Campinas, São Paulo, O Pastore,pt
dc.description.abstractThe effect of silicate anions, from dilute aqueous tetramethylammonium silicate (TMASi) solutions (0-3.0 mmol L(-1) in silicon), on the formation of hexadecyltrimethylammonium bromide (CTAB) micelles was investigated by means of a series of simple conductivity experiments. These two compounds are used in the preparation of mesoporous silicate molecular sieves. An increase in the monovalent silicate anion concentration decreases the critical micelle concentration (cmc) of CTAB, as might be expected from the decreased repulsive forces between the polar heads of the surfactant molecules. However, the decrease in cmc values is less pronounced than that observed in the presence of bromide ions, suggesting that Br- binds more strongly than Si(OH)3O- at the micelle surface. Through the ion-exchange formalism, a selectivity coefficient for Si(OH)3O-/Br- exchange of 0.30+/-0.03 was estimated from the conductivity data. This value compares well with that of 0.4+/-0.1 also determined in this work by the pyrene fluorescence quenching method. The experimental results were used to rationalize the formation of a surfactant supramolecular-templated mesoporous molecular sieve at extremely low surfactant (0.63 mmol L(-1)) and silicate (4.00 mmol L(-1)) concentrations.en
dc.relation.ispartofJournal Of Colloid And Interface Scienceen
dc.relation.ispartofabbreviationJ Colloid Interface Scipt
dc.identifier.citationJournal Of Colloid And Interface Science. v. 299, n. 2, p. 874-82,
dc.description.provenanceMade available in DSpace on 2015-11-27T13:05:17Z (GMT). No. of bitstreams: 1 pmed_16563412.pdf: 247685 bytes, checksum: 6863d16ec86294ce5f778827b5d4289a (MD5) Previous issue date: 2006en
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File SizeFormat 
pmed_16563412.pdf241.88 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.