Evidences for noncondensed counterions in the nonionic-rich composition domain of mixed anionic/nonionic micelles

Treiner, Claude; Fromon, Michel; Mannebach, M. H.

doi:10.1021/la00085a057

Cited by 20 publications

(22 citation statements)

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“…It has been suggested that this behavior is a result of increasing electrostatic interactions between mixed micelles due to the incorporation of charged surfactant. The importance of counterion condensation in modulating these electrostatic interactions in an anionic-nonionic system with added Cu +2 has also been investigated (194).…”

Section: Precipitation Temperatures In Surfactant Mixtures When a Sumentioning

confidence: 99%

Mixed Surfactant Systems

Holland¹,

Rubingh

1992

Mixed Surfactant Systems

254

329

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The properties and behavior of mixed surfactant systems are discussed in the context of experimental techniques and modeling. The overview begins with a general description of mixed surfactant solutions, followed by a more detailed examination of mixed micelles, surfactant mixtures at interfaces, and the phase behavior of mixed systems. Topics include experimental measurements, approaches to modeling, nonideality, unusual surfactant types, micellar demixing, adsorption at various interfaces, chemical reactions in micelles, precipitation, cloud point phenomena and perspectives on the direction of future research on mixed surfactant systems.Mixed surfactant systems are encountered in nearly all practical applications of surfactants. These mixtures arise from several sources. First is the natural polydispersity of commercial surfactants which results from impurities in starting materials and variability in reaction products during their manufacture. These are less expensive to produce than isomerically pure surfactants and often provide better performance. Second is the deliberate formulation of mixtures of different surfactant types to exploit synergistic behavior in mixed systems or to provide qualitatively different types of performance in a single formulation (e.g. cleaning plus fabric softening). Finally, practical formulations often require the addition of surfactant additives to help control the physical properties of the product or improve its stability.

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Section: Precipitation Temperatures In Surfactant Mixtures When a Sumentioning

confidence: 99%

Mixed Surfactant Systems

Holland¹,

Rubingh

1992

Mixed Surfactant Systems

254

329

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“…Previously published data [7,8] using sodium and copper dodecylsulfate as ionic surfactants with C12Fe3 and Triton X-100 as the nonionic components were shown to be compatible with Bjerrum's condition. Zj was assumed to vary linearly with micellar composition, following the simple relationship: Zj = N(1 -XN) where N is the ionic surfactant aggregation number.…”

Section: The Degree Of Dissociation Of Mixed Cationic/nonionic Rnicellesmentioning

confidence: 87%

“…These resuks have some bearing on recent potentiometric studies of counter-ion condensation on mixed ionic/nonionic surfactant systems using ion-selective electrodes [7,8]. The experimental results show that the onset of ion-condensation with mixed anionic/ nonionic micelles is dependent on a critical mixed micellar composition (CMMC).…”

Section: Introductionmentioning

confidence: 90%

“…It has been shown recently [7,8,12,13] with little evidence to the contrary [14] that the counter-ion condensation phenomenon in mixed ionic/nonionic surfactant systems does not start with the first addition of ionic surfactant. There is a composition domain for which the counter-ions do not adsorb at the micellar surface.…”

Section: The Degree Of Dissociation Of Mixed Cationic/nonionic Rnicellesmentioning

confidence: 99%

“…There is a composition domain for which the counter-ions do not adsorb at the micellar surface. We have previously indicated [7,8] that Bierrum's ionic association model suggests an electrostatic condition necessary for ion-condensation, which may be applied to mixed micelles.…”

Section: The Degree Of Dissociation Of Mixed Cationic/nonionic Rnicellesmentioning

confidence: 99%

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Counter ion condensation on mixed cationic/nonionic micellar systems: Bjerrum's electrostatic condition

Treiner

Mannebach

1990

Colloid & Polymer Sci

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Abstract:The association of counter-ions with mixedionic/nonionic micelles has been investigated in the case of dodecyl/tetradecyl/and hexadecyl-trimethylammonium bromide with two nonionic surfactants: dodecylpolyoxyethylene 23 and Triton X-100. The degree of association has been measured by potentiometry using a Bromide ion-selective electrode. Previous results with sodium and copper dodecylsulfate suggesting that in the nonionic-rich composition domain, bare mixed micelles are formed without associated counter-ions have been confirmed. These results are in agreement with the prediction of Bjerrum's condition for ion association. The effect of copper dodecylsulfate on the cloud point of Triton X-100 has also been determined as a means of investigating mixed micelles with multivalent counter-ions. The dramatic cloud point increase observed, even larger than with sodium dodecylsulfate, has been discussed as evidence of the solvation of divalent ions by ether groups, a factor which complicates the analysis of multivalent counterion condensation on mixed micelles.

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