Étude de microémulsions en résonance magnétique nucléaire à haut champ

Biais, J.; Clin, B.; Lalanne, P.; Lemanceau, Bernard

doi:10.1051/jcp/1977741197

Cited by 22 publications

(8 citation statements)

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“…23,24 For surfactants having a small packing parameter, e.g., sodium dodecyl sulfate or CTAC, on the other hand, the addition of a co-surfactant, e.g., 1-hexanol, will result in the formation of a stable microemulsion. [25][26][27] This additional stability is attributed to the alcohol molecules, which reduce the surface charge density of the micelle by intercalating among the interfacial surfactant molecules and increasing the separations between the ionic head groups of the surfactants. [28][29][30] Additionally, the alcohol co-surfactants also influence the kinetics of reactions in the reverse micelles as well as the polarity of the micellar medium.…”

Section: Resultsmentioning

confidence: 99%

An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

et al. 2006

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Amphiphilic molecules (surfactants) when dissolved in a bulk organic non-polar solvent form organized assemblies called reverse micelles when an appropriate concentration of surfactants, the critical micellar concentration, is reached. 1 The structure of a reverse micelle is the inverse prototype of the normal micellar structure. The polar head groups of the surfactant molecules are in contact with the tiny water pool (containing the associated counter ions) in the core of the reverse micelle while the hydrophobic chains are directed outward into the bulk organic solvent. In our previous work, chemiluminescence (CL) generation was observed upon mixing iodine with luminol dispersed in the carbonate-buffered water pool of the reversed micelle of cetyltrimethylammonium chloride (CTAC). 2 Absorption measurements demonstrated that, on mixing of the cyclohexane solution of iodine with the CTAC reversed micellar solution, iodine could be transferred instantly and completely from the organic phase into the buffered water pool of the reverse micelle.2 On the other hand, when iodine was premixed with the reversed micellar solution containing the carbonate buffer alone and then the resulting mixture was mixed with the reversed micellar solution of luminol, no CL emission was produced. 3 In the CL reaction of luminol with iodine, hypoiodous acid and the iodite ion have been proposed as oxidants in usual alkaline aqueous solutions. 4 Thus, a possible explanation would be that, on iodine uptake by the reverse micelle, these oxidizing agents may be produced initially and be present transiently at the surfactant-water pool interface, before reacting immediately with luminol anion to generate luminescence. 2,3 The chloride ion, the counter ion of CTAC, is also presumed to be available mostly at the surfactant-water pool interface, 5 and to cause its association with iodine. 6 This might facilitate the quantitative uptake of iodine by the CTAC reverse micelle. In addition, the concentration effect of iodine can be achieved by entrance of iodine into a small volume of the interfacial region in the CTAC reverse micelles, where acceleration of the luminol CL reaction seems likely due to more efficient association of luminol with the generated oxidants, resulting in the generation of more intense or higher CL signals.Several metal ions present in aqueous samples may interfere with iodine determination by using the usual aqueous phase luminol CL reaction; thus, their removal is needed by incorporating separation science techniques into the procedure. 7 When iodide is oxidized into iodine, since iodide is not CLactive, subsequent separation from the oxidant used which could interfere with the CL determination is also required. 2,3,8 One of the effective methods of preconcentration and separation of iodine from such interferents as oxidant and metallic species is its extraction with a suitable organic solvent. Yasuda Women's College, Yasuhigashi, Japan To eliminate the use of chlorinated hydrocarbons, we have improved the method for...

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Section: Resultsmentioning

confidence: 99%

An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

et al. 2006

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“…Many authors have studied the influence of the amount of salt or cosurfactant on the modification of the macroscopic state of the system (Winsor types I, II, III, IV) [31,32].…”

Section: Effect Of the Butan-1-ol: Surfactant Ratiomentioning

confidence: 99%

Phase behavior of pseudoternary brine/alkane/alcohol-secondary alkanesulfonates systems

Azira

Tazerouti²,

Canselier

2008

J Therm Anal Calorim

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“…We have been able (Biais et al, 1977b), among others (Hansen, 1974), to show that one of the most important properties of microemulsions is the high dynamics of their constituting molecules. Furthermore, it is well known that the structure and the stability of such systems are very sensitive to any composition or temperature modification (Robbins, 1977).…”

Section: (A) General Considerationsmentioning

confidence: 92%

Microemulsions and electron microscopy

Biais

Mercier

Bothorel

et al. 1981

Journal of Microscopy

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SUMMARY The replicas obtained from various microemulsions prepared under different freezing conditions were observed by electron microscopy. The difficulties encountered in obtaining proper freezing may be related to the peculiar properties of such systems. A proposal is made for using systems with particular physical characteristics, which preserve the micellar structure during freezing, instead of looking for perfect freezing conditions. This proposal proved to be successful.

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Étude de microémulsions en résonance magnétique nucléaire à haut champ

Cited by 22 publications

References 0 publications

An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

Phase behavior of pseudoternary brine/alkane/alcohol-secondary alkanesulfonates systems

Microemulsions and electron microscopy

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