Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study
Autor(a) principal: | |
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Data de Publicação: | 2000 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://hdl.handle.net/11449/224187 |
Resumo: | We have used isothermal titration calorimetry to investigate the vesicle-to-micelle transition in dioctadecyldimethylammonium bromide (DODAB) and chloride (DODAC) vesicle dispersions induced by the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) at room temperature. Small and giant unilamellar vesicles were prepared by sonication and without sonication, respectively, of the pure cationic surfactants at low concentrations in water. The titration of 1.0 mM DODAX (X = Cl- and Br-) by a concentrated micellar solution of C12E8 shows that the enthalpy of interaction (ΔHobs) of C12E8 in micellar form with DODAX is always endothermic. The titration curves are understood on the basis of superposition of the enthalpies of partitioning of C12E8 into the bilayer, of micelle formation and of vesicle-to-micelle transformation. The enthalpy, ΔHobs, initially increases owing to the incorporation of C12E8 into the vesicle bilayer until the C12E8/DODAX saturation ratio (Rsat) is reached, then ΔHobs decreases, in different ways for DODAB and DODAC, owing to degradation of vesicles and formation of mixed micelles and intermediary structures up to the C12E8/ DODAX solubilization ratio, Rsol. Above Rsol only mixed micelles exist. The surfactant solubilization takes place in three stages. All the critical ratios are lower for DODAB than for DODAC, meaning that C12E8 solubilizes more strongly in DODAB; for example, Rsat is 0.8 for DODAB and 1.2 for DODAC. Sonication has no significant effect on the transition. © Springer-Verlag 2000. |
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Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry studyCationic vesiclesDioctadecyldimethylammonium bromideDioctadecyldimethylammonium chlorideIsothermal titration calorimetrySurfactant solubilizationWe have used isothermal titration calorimetry to investigate the vesicle-to-micelle transition in dioctadecyldimethylammonium bromide (DODAB) and chloride (DODAC) vesicle dispersions induced by the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) at room temperature. Small and giant unilamellar vesicles were prepared by sonication and without sonication, respectively, of the pure cationic surfactants at low concentrations in water. The titration of 1.0 mM DODAX (X = Cl- and Br-) by a concentrated micellar solution of C12E8 shows that the enthalpy of interaction (ΔHobs) of C12E8 in micellar form with DODAX is always endothermic. The titration curves are understood on the basis of superposition of the enthalpies of partitioning of C12E8 into the bilayer, of micelle formation and of vesicle-to-micelle transformation. The enthalpy, ΔHobs, initially increases owing to the incorporation of C12E8 into the vesicle bilayer until the C12E8/DODAX saturation ratio (Rsat) is reached, then ΔHobs decreases, in different ways for DODAB and DODAC, owing to degradation of vesicles and formation of mixed micelles and intermediary structures up to the C12E8/ DODAX solubilization ratio, Rsol. Above Rsol only mixed micelles exist. The surfactant solubilization takes place in three stages. All the critical ratios are lower for DODAB than for DODAC, meaning that C12E8 solubilizes more strongly in DODAB; for example, Rsat is 0.8 for DODAB and 1.2 for DODAC. Sonication has no significant effect on the transition. © Springer-Verlag 2000.Physical Chemistry 1 Center for Chemistry and Chemical Engineering University of Lund, P.O. Box 124, 221 00 LundPhysics Department IBILCE/UNESP, 15054-000 Sao Jose do Rio Preto, SPPhysics Department IBILCE/UNESP, 15054-000 Sao Jose do Rio Preto, SPUniversity of LundUniversidade Estadual Paulista (UNESP)Barreleiro, P. C.A.Olofsson, G.Feitosa, E. [UNESP]2022-04-28T19:55:04Z2022-04-28T19:55:04Z2000-12-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article33-36Progress in Colloid and Polymer Science, v. 116, p. 33-36.0340-255Xhttp://hdl.handle.net/11449/2241872-s2.0-0034591941Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengProgress in Colloid and Polymer Scienceinfo:eu-repo/semantics/openAccess2022-04-28T19:55:04Zoai:repositorio.unesp.br:11449/224187Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T20:12:18.601487Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study |
title |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study |
spellingShingle |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study Barreleiro, P. C.A. Cationic vesicles Dioctadecyldimethylammonium bromide Dioctadecyldimethylammonium chloride Isothermal titration calorimetry Surfactant solubilization |
title_short |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study |
title_full |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study |
title_fullStr |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study |
title_full_unstemmed |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study |
title_sort |
Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study |
author |
Barreleiro, P. C.A. |
author_facet |
Barreleiro, P. C.A. Olofsson, G. Feitosa, E. [UNESP] |
author_role |
author |
author2 |
Olofsson, G. Feitosa, E. [UNESP] |
author2_role |
author author |
dc.contributor.none.fl_str_mv |
University of Lund Universidade Estadual Paulista (UNESP) |
dc.contributor.author.fl_str_mv |
Barreleiro, P. C.A. Olofsson, G. Feitosa, E. [UNESP] |
dc.subject.por.fl_str_mv |
Cationic vesicles Dioctadecyldimethylammonium bromide Dioctadecyldimethylammonium chloride Isothermal titration calorimetry Surfactant solubilization |
topic |
Cationic vesicles Dioctadecyldimethylammonium bromide Dioctadecyldimethylammonium chloride Isothermal titration calorimetry Surfactant solubilization |
description |
We have used isothermal titration calorimetry to investigate the vesicle-to-micelle transition in dioctadecyldimethylammonium bromide (DODAB) and chloride (DODAC) vesicle dispersions induced by the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) at room temperature. Small and giant unilamellar vesicles were prepared by sonication and without sonication, respectively, of the pure cationic surfactants at low concentrations in water. The titration of 1.0 mM DODAX (X = Cl- and Br-) by a concentrated micellar solution of C12E8 shows that the enthalpy of interaction (ΔHobs) of C12E8 in micellar form with DODAX is always endothermic. The titration curves are understood on the basis of superposition of the enthalpies of partitioning of C12E8 into the bilayer, of micelle formation and of vesicle-to-micelle transformation. The enthalpy, ΔHobs, initially increases owing to the incorporation of C12E8 into the vesicle bilayer until the C12E8/DODAX saturation ratio (Rsat) is reached, then ΔHobs decreases, in different ways for DODAB and DODAC, owing to degradation of vesicles and formation of mixed micelles and intermediary structures up to the C12E8/ DODAX solubilization ratio, Rsol. Above Rsol only mixed micelles exist. The surfactant solubilization takes place in three stages. All the critical ratios are lower for DODAB than for DODAC, meaning that C12E8 solubilizes more strongly in DODAB; for example, Rsat is 0.8 for DODAB and 1.2 for DODAC. Sonication has no significant effect on the transition. © Springer-Verlag 2000. |
publishDate |
2000 |
dc.date.none.fl_str_mv |
2000-12-01 2022-04-28T19:55:04Z 2022-04-28T19:55:04Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
Progress in Colloid and Polymer Science, v. 116, p. 33-36. 0340-255X http://hdl.handle.net/11449/224187 2-s2.0-0034591941 |
identifier_str_mv |
Progress in Colloid and Polymer Science, v. 116, p. 33-36. 0340-255X 2-s2.0-0034591941 |
url |
http://hdl.handle.net/11449/224187 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Progress in Colloid and Polymer Science |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
33-36 |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
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1808129171437649920 |