Micellization 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 concentrations

dc.creatorVautier-Giongo, C
dc.creatorPastore, HO
dc.date2006
dc.date42186
dc.date2014-11-17T03:19:35Z
dc.date2015-11-26T16:36:43Z
dc.date2014-11-17T03:19:35Z
dc.date2015-11-26T16:36:43Z
dc.date.accessioned2018-03-28T23:19:33Z
dc.date.available2018-03-28T23:19:33Z
dc.identifierJournal Of Colloid And Interface Science. Academic Press Inc Elsevier Science, v. 299, n. 2, n. 874, n. 882, 2006.
dc.identifier0021-9797
dc.identifierWOS:000238294800049
dc.identifier10.1016/j.jcis.2006.02.040
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/56667
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/56667
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/56667
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1271891
dc.descriptionThe 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)(3)O- at the micelle surface. Through the ion-exchange formalism, a selectivity coefficient for Si(OH)(3)O-/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. (c) 2006 Elsevier Inc. All rights reserved.
dc.description299
dc.description2
dc.description874
dc.description882
dc.languageen
dc.publisherAcademic Press Inc Elsevier Science
dc.publisherSan Diego
dc.publisherEUA
dc.relationJournal Of Colloid And Interface Science
dc.relationJ. Colloid Interface Sci.
dc.rightsfechado
dc.rightshttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dc.sourceWeb of Science
dc.subjectmesoporous molecular sieves
dc.subjectCTAB
dc.subjectmicellization
dc.subjectsurfactant
dc.subjectsilicate
dc.subjectPoisson-boltzmann Equation
dc.subjectIn-situ Investigations
dc.subjectIon-exchange
dc.subjectCetyltrimethylammonium Micelles
dc.subjectFormation Mechanism
dc.subjectCounterion Binding
dc.subjectPseudophase Model
dc.subjectCationic Micelles
dc.subjectTemplated Silica
dc.subjectHydroxide Ion
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 concentrations
dc.typeArtículos de revistas


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