Fluorescence methods in the study of the interactions of surfactants with polymers

Winnik, Françoise M.; Regismond, S.T.A.

doi:10.1016/0927-7757(96)03733-8

Cited by 340 publications

(343 citation statements)

References 141 publications

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Section: Fluorescence Measurementsmentioning

confidence: 99%

“…5,33,37,38,40,41 They are undoubtedly useful in determining key parameters, such as cmc and cac. The fluorescent probe pyrene has five fluorescent bands and the ratio between its I 1 (372.8 nm) and I 3 (384.0 nm) bands is sensitive to small changes in the environmental polarity.…”

Section: Fluorescence Measurementsmentioning

confidence: 99%

“…The I 1 /I 3 ratio was estimated by taking into account the ratio of the maximum peak intensity at 372.8 nm (I 1 ) and at 384.0 nm (I 3 ). [37][38][39][40][41] …”

Section: Steady-state Fluorescencementioning

confidence: 99%

“…0.6 for hexane. 40,41 Since the pyrene probe migrates from the polar aqueous medium to the apolar micellar cores during the surfactant micellization, the I 1 /I 3 ratio becomes possible to follow the aggregation path.The profiles of I 1 /I 3 ration vs.[SDS] and [NaC] in PEI-free solution and in the presence of 0.2% m/v PEI are shown in Figures 4A and 4B, respectively. The I 1 /I 3 ratio in the presence of small amounts of SDS or NaC is around 1.80-1.85, what is consistent with the water polarity.…”

mentioning

confidence: 99%

“…It is possible to monitor pyrene migration from a polar (water) to an apolar (micellar core) environment through the fluorescence spectroscopy by measuring the I 1 /I 3 ratio. 40,41 The I 1 /I 3 ratio of pyrene is used as a criterion to evaluate the micropolarity of the microenvironments of micellar aggregates, and extreme values of this polarity scale comprise ca. 1.8 for water and ca.…”

mentioning

confidence: 99%

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Supramolecular complexes formed by the association of poly(ethyleneimine) (PEI), sodium cholate (NaC) and sodium dodecyl sulfate (SDS)

Felippe

Bellettini

Eising

et al. 2011

J. Braz. Chem. Soc.

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A formação de complexos supramoleculares em solução aquosa pela associação do polieletrólito poli(etilenoimina) (PEI) com misturas do biossurfactante colato de sódio (NaC) e o surfactante aniônico dodecil sulfato de sódio (SDS) foi aqui investigado usando as técnicas de condutivimetria, tensiometria, fluorimetria, espalhamento de raios X a baixos ângulos (SAXS) e medidas de pH. Os resultados de fluorimetria, condutivimetria e medidas de pH levaram à conclusão de que os monômeros de NaC e SDS ligam-se primeiramente em sítios específicos das cadeias do polieletrólito PEI via interação eletrostática e posteriormente através de associação cooperativa. A interação do NaC com o PEI é mais fraca do que a interação do SDS com o PEI, porém, a adição de SDS ao sistema NaC-PEI levou à formação de micelas mistas SDS-NaC que interagiram fortemente com o polieletrólito PEI. Os resultados de SAXS sugeriram que o complexo supramolecular possui característica elipsoidal e essa forma não depende da concentração de surfactante nem da χ NaC .The formation of supramolecular complexes produced by association of poly(ethyleneimine) (PEI) and mixtures of sodium cholate (NaC) and sodium dodecyl sulfate (SDS) was investigated by pH, electrical conductivity, fluorescence spectroscopy and small angle X-ray scattering (SAXS) measurements. The fluorescence linked to previously measured values of pH and conductivity led to the conclusion that NaC and SDS molecules firstly bind to specific sites of the PEI chains via electrostatic interaction and secondly undergo self-assembly through regular cooperative association. The interaction of NaC with the polyelectrolyte PEI is weaker than that of SDS and the addition of SDS to the NaC-PEI system led to the formation of mixed NaC-SDS micelles which stronger interact with PEI. The SAXS results suggested that the micellar aggregates have a considerably ellipsoidal characteristic and the micellar shape is not affected by the surfactant concentration nor by χ NaC .Keywords: sodium cholate, sodium dodecyl sulfate, poly(ethyleneimine), polymer-surfactants interaction IntroductionBile salts are naturally-occurring amphiphilic molecules. They are physiologically important in the solubilization and transport of fats and lipids. The structure of bile salts in water has been extensively investigated. Although they are comparable to common surfactants, the general conclusion is that biosurfactants self-assemble in a different way than the standard surfactants. [1][2][3][4][5][6][7][8][9][10][11][12][13] Poly(ethyleneimine) (PEI) is a member of a large family of water-soluble polyamines having different molecular weights (M w ) and polymer architectures. Polyamines are weak bases and exhibit a cationic character depending on the degree of protonation. PEI has been extensively studied (particularly the branched form) due to its intense use in the formulation of drugs, thickeners, flocculating agents, personal care products, food products, detergents and adhesives. It has also been used for biological proposes to p...

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Section: Fluorescence Measurementsmentioning

confidence: 99%

Section: Fluorescence Measurementsmentioning

confidence: 99%

“…The I 1 /I 3 ratio was estimated by taking into account the ratio of the maximum peak intensity at 372.8 nm (I 1 ) and at 384.0 nm (I 3 ). [37][38][39][40][41] …”

Section: Steady-state Fluorescencementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Supramolecular complexes formed by the association of poly(ethyleneimine) (PEI), sodium cholate (NaC) and sodium dodecyl sulfate (SDS)

Felippe

Bellettini

Eising

et al. 2011

J. Braz. Chem. Soc.

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Interactions between Chromophore-Labelled Ammonium Surfactants and Hydrophobically Modified Polyelectrolytes

Nieuwkerk¹,

Kan²,

Koudijs³

et al. 1999

Eur. J. Org. Chem.

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The interaction of poly(maleic acid‐co‐alkyl vinyl ether)s and poly(sulfonylethyl maleic acid monoamide‐co‐alkyl vinyl ether)s with and without (cyanobiphenylyl)oxy chromophores with N‐[ω‐(substituted azobenzoxy)alkyl]‐N,N‐dimethyl‐N‐hydroxyethylammonium bromide surfactants has been studied by UV spectroscopy. The azobenzene unit is functionalized at the 4′‐position with a cyano or fluoro substituent and is connected to the surfactant headgroup via a decyl or dodecyl spacer. Upon addition of surfactants to poly(maleic acid‐co‐butyl vinyl ether) the absorption maxima (λmax) of the azobenzene chromophores immediately show their maximum blue shift. This indicates cooperative binding of surfactant to this polymer, and the formation of micelle‐like aggregates surrounded by polyelectrolyte is assumed. Upon addition of the surfactants to the other polyelectrolytes λmax values of the azobenzoxy chromophores gradually shift to lower values indicating a lower cooperativity of surfactant binding. This is attributed to the formation of microdomains by the polyelectrolytes themselves. For these systems the formation of mixed micelles is assumed. The compactness of the microdomains of the maleic acid copolymers is influenced by the pH and binding with surfactants is also influenced by pH. The sulfonylethyl maleic acid monoamide copolymers show no pH dependence in binding above neutral pH. For these polyelectrolytes the cooperativity also becomes less with a longer spacer between backbone and chromophore. Upon elongation of the surfactant spacer or changing the end group from a cyano to the more hydrophobic fluoro substituent a lower λmaxis observed for the chromophores upon initial binding to the polyelectrolytes indicating more cooperative binding. When surfactants and polyelectrolytes are both labelled with chromophores, binding proceeds noncooperatively and the formation of mixed micelles is assumed.

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On-Line Monitoring of Chemical Reactions

Hergeth¹

2000

Ullmann's Encyclopedia of Industrial Chemistry

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Fluorescence methods in the study of the interactions of surfactants with polymers

Cited by 340 publications

References 141 publications

Supramolecular complexes formed by the association of poly(ethyleneimine) (PEI), sodium cholate (NaC) and sodium dodecyl sulfate (SDS)

Supramolecular complexes formed by the association of poly(ethyleneimine) (PEI), sodium cholate (NaC) and sodium dodecyl sulfate (SDS)

Interactions between Chromophore-Labelled Ammonium Surfactants and Hydrophobically Modified Polyelectrolytes

On-Line Monitoring of Chemical Reactions

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