ESR spin probe study of micelle-polymer complexes. Poly(ethylene oxide)- and poly(propylene oxide)-complexed sodium dodecyl sulfate and cetyltrimethylammonium bromide micelles

Witte, Frank M.; Engberts, Jan B. F. N.

doi:10.1021/jo00248a033

Cited by 27 publications

(15 citation statements)

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“…Thus they should move to the surface of micelles and subject to intra-and inter-micellar diffusion (Castle and Perkins, 1986) more quickly in SDS than in CTAB micelles, so as to react with the antioxidant whose reactive phenoxyl functional group shall reside on the surface of the micelles (Castle and Perkins, 1986). In addition, the microviscosity in the interior of CTAB micelle is 2.6 times larger than that of SDS micelle (Witte and Engberts, 1988), making the intra-micellar diffusion slower in CTAB micelle. It has been proved previously that intra-and inter-micellar diffusions are rate-limiting steps for the antioxidation reaction conducted in micelles (Castle and Perkins, 1986;Liu et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Dai

Chen

Zhou

et al. 2009

Phytotherapy Research

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Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, 1) is a yellow ingredient isolated from turmeric (curcumin longa). Many health benefits have been claimed for curcumin, and these have generally been ascribed to its radical-trapping antioxidant properties. In order to find more active antioxidants with 1 as the lead compound, we synthesized curcumin analogues, i.e., 1,7-bis(3,4-dihydroxyphenyl)-1,6-heptadiene-3,5-dione (2), 1-(3,4-dihydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (3), 1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (4), 1,7-bis (4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (5), 1,7-bis(3,4-dimethoxyphenyl)-1,6-heptadiene-3,5-dione (6), 1,7-bis(4-methoxyphenyl)-1,6-heptadiene-3,5-dione (7), and 1,7-diphenyl-1,6-heptadiene-3,5-dione (8). Antioxidative effects of curcumin and these analogues against the peroxidation of linoleic acid were studied in sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) micelles. The peroxidation was initiated thermally by a water-soluble initiator 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), and reaction kinetics were monitored by the formation of linoleic acid hydroperoxides. Kinetic analysis of the antioxidation process demonstrates that these compounds, except 6, 7 and 8, are effective antioxidants in micelles by H-atom abstraction from the phenolic groups. Compounds 2 and 3, which bear ortho-diphenoxyl functionality, possess significantly higher antioxidant activity than curcumin and other analogues, and the 4-hydroxy-3-methoxyphenyl group also plays an important role in the antioxidative activity. In addition, the synergistic antioxidant effect of these compounds with alpha-tocopherol (vitamin E) in micelles was also studied by following the formation of linoleic acid hydroperoxides and the consumption of alpha-tocopherol. It was found that these compounds could not synergistically interact with alpha-tocopherol in micelles.

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Section: Discussionmentioning

confidence: 99%

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Dai

Chen

Zhou

et al. 2009

Phytotherapy Research

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“…38,39 or the microenvironment sensed by the spin probes used in the ESR measurements in the presence and in the absence of polymers. 40 In addition, micellar ionization degrees rise with the PPG molecular weight. The same effect has been found in both cationic surfactant/polymer systems 22 as well as in anionic surfactant/polymer systems, 10 and the same effect is produced by incorporating medium-chain alcohols into the micelles.…”

Section: Discussionmentioning

confidence: 99%

Aggregation Model That Describes the Physical Properties of the Sodium Dodecyl Sulfate/Poly(propylene glycol) System in Aqueous Solution

Rodenas

Sierra

1996

Langmuir

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Micellar ionization degrees, from conductivity measurements, and micellar aggregation numbers, from steady-state quenching fluorescence of the sodium dodecyl sulfate/poly(propylene glycol) (SDS/PPG) (MW ) 425 and 1000) systems in aqueous solution, have been obtained. From the experimental results we conclude that small aggregates form on the polymer chain at a surfactant concentration c 1 smaller than the surfactant cmc. The aggregation numbers of these aggregates sharply increase with SDS concentration and, at a critical surfactant concentration (c2) higher than the SDS cmc, the aggregates become large enough to incorporate the polymer chains into the surfactant micelles, forming SDS/PPG mixed micelles in aqueous solution, that are similar to the cetyltrimethylammonium bromide (CTAB)/PPG and surfactant/ medium chain alcohols mixed micelles.

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“…Several investigators discussed the models of complexation (5)(6)(7)(8): among them, Ruckenstein et aL (7) considered that the presence of polymer molecules in water changes the microenvironment of the surfactant molecules and alters particularly the interracial free energy between the hydrocarbon core of the micellar aggregate and the water located in the "free space" of the coiled macromolecules.…”

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confidence: 99%

Association of nonionic polymer with hydrocarbon/fluorocarbon surfactant in aqueous solution

Nojima

Esumi

Meguro

1992

J Americ Oil Chem Soc

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The interaction between a nonionic polymer and a hydrocarbon or fluorocarbon surfactant has been investigated by means of surface tension, viscosity, electroconductivity, fluorescence probing, solubilization of a waterinsoluble dye, and electron spin resonance (ESR}. The systems studied consisted of polyvinylpyrrolidone (PVP) with lithium dodecyl sulfate (I,|DS) or lithium perfluoroo~ tane sulfonate (LiFOS). Surface tension measurements indicated that formation of PVP~surfactant complex is more favorable in the PVP-LiFOS system than in the PVP-LiDS system, and that the adsorbed amount of LiFOS is less than that of LIDS, although the CMCs of the surfactants are almost the same. In the PVP-LiFOS system, the relative viscosity and the solubilized amount of a water-insohible dye showed a maximum at a certain concentration of LiFOS in the region between two transitions observed in the surface tension, where also a change in the slope of the electroconductivity is observed. These results indicate that shielding of effective charge of the PVpoLiFOS complex causes a conformational change of PVP wrapped around the aggregate of LiFOS with an increase of free surfactant in the bulk phase. The conformational change can be correlated with microenviroumental properties of PVP-surfactant complexes. The microviscosity estimated with ESR indicated that the headgroups of LiFOS adsorbed on PVP are less tightly packed than those of LiFOS micelles, while an opposite result was obtained in the PVP-LiDS system. In particular, the marked high viscosity at a low concentration of LiFOS in the PVP-LiFOS system can probably be attributed to rigidity of the fluorocarbon chain of LiFOS.KEY WORDS: Lithium dodecyl sulfate, lithium perfluorooctane sulfonate, micvoenvironmental property, PVP-perfluorinated surfactant, solubilization of dye.

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ESR spin probe study of micelle-polymer complexes. Poly(ethylene oxide)- and poly(propylene oxide)-complexed sodium dodecyl sulfate and cetyltrimethylammonium bromide micelles

Cited by 27 publications

References 0 publications

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Aggregation Model That Describes the Physical Properties of the Sodium Dodecyl Sulfate/Poly(propylene glycol) System in Aqueous Solution

Association of nonionic polymer with hydrocarbon/fluorocarbon surfactant in aqueous solution

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