Interaction between poly(ethylene glycol) and C12E8 investigated by dynamic light scattering, time-resolved fluorescence quenching, and calorimetry

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dc.contributor.authorFeitosa, E.
dc.contributor.authorBrown, W.
dc.contributor.authorWang, K.
dc.contributor.authorBarreleiro, PCA
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniv Uppsala
dc.contributor.institutionLund Univ
dc.date.accessioned2014-05-20T15:26:52Z
dc.date.available2014-05-20T15:26:52Z
dc.date.issued2002-01-01
dc.description.abstractDynamic light scattering (DLS), time-resolved fluorescence quenching (TRFQ), and isothermal titration microcalorimetry have been used to show that, in dilute solution, low molecular weight poly(ethylene glycol) (PEG, M-w = 12 kDa) interacts with the nonionic surfactant octaethylene glycol n-dodecyl monoether, C12E8, to form a complex. Whereas the relaxation time distributions for the binary C12E8/water and PEG/water systems are unimodal, in the ternary mixtures they may be either uni- or bimodal depending on the relative concentrations of the components. At low concentrations of PEG or surfactant, the components of the relaxation time distribution are unresolvable, but the distribution becomes bimodal at higher concentrations of either polymer or surfactant. For the ternary system in excess surfactant, we ascribe, on the basis of the changes in apparent hydrodynamic radii and the scattered intensities, the fast mode to a single micelle, the surface of which is associated with the polymer and the slow mode to a similar complex but containing two or three micelles per PEG chain. Titration microcalorimetry results show that the interaction between C12E8, and PEG is exothermic and about 1 kJ mol(-1) at concentrations higher than the CMC of C12E8. The aggregation number, obtained by TRFQ, is roughly constant when either the PEG or the C12E8 concentration is increased at a given concentration of the second component, owing to the increasing amount of surfactant micelles inside the complex.en
dc.description.affiliationUNESP, IBILCE, Dept Fis, BR-15055000 Sao Jose do Rio Preto, SP, Brazil
dc.description.affiliationUniv Uppsala, Dept Phys Chem, S-75121 Uppsala, Sweden
dc.description.affiliationLund Univ, Ctr Chem & Chem Engn, S-22100 Lund, Sweden
dc.description.affiliationUnespUNESP, IBILCE, Dept Fis, BR-15055000 Sao Jose do Rio Preto, SP, Brazil
dc.format.extent201-207
dc.identifierhttp://dx.doi.org/10.1021/ma010696w
dc.identifier.citationMacromolecules. Washington: Amer Chemical Soc, v. 35, n. 1, p. 201-207, 2002.
dc.identifier.doi10.1021/ma010696w
dc.identifier.issn0024-9297
dc.identifier.urihttp://hdl.handle.net/11449/36947
dc.identifier.wosWOS:000173023200028
dc.language.isoeng
dc.publisherAmer Chemical Soc
dc.relation.ispartofMacromolecules
dc.relation.ispartofjcr5.914
dc.relation.ispartofsjr2,419
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.titleInteraction between poly(ethylene glycol) and C12E8 investigated by dynamic light scattering, time-resolved fluorescence quenching, and calorimetryen
dc.typeArtigo
dcterms.licensehttp://pubs.acs.org/paragonplus/copyright/jpa_form_a.pdf
dcterms.rightsHolderAmer Chemical Soc
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Biociências Letras e Ciências Exatas, São José do Rio Pretopt

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Artigos - Física - IBILCE