Study of mixed aggregates in aqueous solutions of sodium dodecyl sulfate and dodecyltrimethylammonium bromide

Kamenka, N.; Chorro, M.; Talmon, Yeshayahu; Zana, R.

doi:10.1016/0166-6622(92)80300-q

Cited by 79 publications

(95 citation statements)

References 41 publications

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“…[1][2][3][4][5][6] Such catanionic mixtures are well-known to form vesicles spontaneously, as shown for a variety of systems of single alkyl chain [7][8][9][10] or double alkyl chain surfactants 11 and for these systems energetically stabilized vesicles are predicted on a theoretical basis. 12 In addition, it is also possible to have entropic stabilisation of vesicles which can occur for bilayers with low bending rigidity.…”

Section: Introductionmentioning

confidence: 99%

Phase behaviour and structure of zwitanionic mixtures of perfluorocarboxylates and tetradecyldimethylamine oxide—dependence on chain length of the perfluoro surfactant

et al. 2011

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Phase behaviour and the mesoscopic structure of zwitanionic surfactant mixtures based on the zwitterionic tetradecyldimethylamine oxide (TDMAO) and anionic lithium perfluoroalkyl carboxylates have been investigated for various chain lengths of the perfluoro surfactant with an emphasis on spontaneously forming vesicles. These mixtures were studied at a constant total concentration of 50 mM and characterised by means of dynamic light scattering (DLS), electric conductivity, small-angle neutron scattering (SANS), viscosity, and cryo-scanning electron microscopy (Cryo-SEM). No vesicles are formed for relatively short perfluoro surfactants. The extension of the vesicle phase becomes substantially larger with increasing chain length of the perfluoro surfactant, while at the same time the size of these vesicles increases. Head group interactions in these systems play a central role in the ability to form vesicles, as already protonating 10 mol% of the TDMAO largely enhances the propensity for vesicle formation. The range of vesicle formation in the phase diagram is not only substantially enlarged but also extends to shorter perfluoro surfactants, where without protonation no vesicles would be formed. The size and polydispersity of the vesicles are related to the chain length of the perfluoro surfactant, the vesicles becoming smaller and more monodisperse with increasing perfluoro surfactant chain length. The ability of the mixed systems to form well-defined unilamellar vesicles accordingly can be controlled by the length of the alkyl chain of the perfluorinated surfactant and depends strongly on the charge conditions, which can be tuned easily by pH-variation.

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Section: Introductionmentioning

confidence: 99%

Phase behaviour and structure of zwitanionic mixtures of perfluorocarboxylates and tetradecyldimethylamine oxide—dependence on chain length of the perfluoro surfactant

et al. 2011

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“…These data support the view that DeTAB and DTAB become totally absorbed into SDS micelles in the clear, SDS-rich part of the phase diagrams. The two cationic surfactants are assimilated as in the case of any hydrophobic molecule, without causing any great change in the SDS micelle size or shape (2).…”

Section: Results and Discussion ( A ) Solubilitiesmentioning

confidence: 99%

“…A total incorporation of oppositely charged DTAB or DeTAB into the SDS micelles would have to occur to explain the precipitous decline of KNi from 220 to 30 when 20 mol% of cationic surfactant is present. On being assimilated within the SDS micelles, the cationic monomers displace the Naf counterions leading to a lower effective micellar charge (2). At 30 mol% DTAB, the kinetic analysis according to the Robinson equation by which the values of KNi and V might be obtained proved intractable, signifying a breakdown in the modelling situation.…”

Section: (B) Rate Enhancemerztsmentioning

confidence: 99%

“…At 30 mol% DTAB, the kinetic analysis according to the Robinson equation by which the values of KNi and V might be obtained proved intractable, signifying a breakdown in the modelling situation. Indeed, Kamenka et al (2) had found evidence of vesicle formation beyond 30 mol% in this same system and, in an allied system involving SDS, Marques et al (13) reported vesicles in even dilute surfactant solutions. Spontaneous vesicle formation is commonplace with catanionic surfactants that are essentially 1:l combinations of anionic and cationic surfactants but with the counterions removed (14 no-charge situation but even at 30 mol% DTAB the electrostatic attraction experienced by ~i ' + ( ,~, with the mixed micelle or vesicle must be greatly reduced.…”

Section: (B) Rate Enhancemerztsmentioning

confidence: 99%

“…The percent of DTAB or DeTAB solubilization is open to question but Kamenka et al (2) have reported that their tracer self-diffusion and specific electrode potentiometry results signify that all the DTAB is accommodated by SDS micelles without any apprecible increase in size. Our work concurs with this assessment.…”

Section: (B) Rate Enhancemerztsmentioning

confidence: 99%

See 2 more Smart Citations

Micellar catalysis in mixed anionic/cationic surfactant systems

Favaro¹,

Reinsborough²

1994

Can. J. Chem.

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. Can. J. Chem. 72,2443Chem. 72, (1994.Dye solubility and stopped-flow kinetic studies were conducted in sodium dodecylsulfate/dodecyltrimethylammonium bromide and sodium dodecylsulfate/decyltrimethylammonium bromide micellar solutions with excess anionic surfactant. The enhanced rate in the presence of anionic micelles of the ~i~+~,,,l~~ridine-2-azo-~-dimeth~laniline (PADA) complexation reaction was used as a probe of the mixed micellar situation. PADA solubilities and the kinetic parameters derived through the Robinson model for micellar catalysis were consistent with a complete incorporation of the cationic surfactant into the sodium dodecylsulfate micelles.

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Electron microscopy studies of amphiphilic self‐assemblies on vitreous ice

et al. 1995

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The structure of self-assemblies of amphiphiles formed at the air-aqueous solution interface can be determined by cryotransmission electron microscopy (Cryo-TEM). The method is based on fast vitrification of the thin layer of aqueous solution covered with amphiphilic monolayer by plunging the specimen into liquid ethane at its freezing point. During the process of fast cooling the aggregates maintain their two-dimensional crystalline integrity and structure, as demonstrated by comparative studies involving grazing incidence X-ray diffraction (GID) at the air-solution interface, and the Cryo-TEM measurements of the same amphiphilic systems on vitreous ice. Bright-field and dark-field images from the Cryo-TEM observations provide more detailed information than from epifluorescence and Brewster angle microscopy. Furthermore, the electron diffraction patterns have the additional advantage that they allow structural characterization of the crystallites almost at a molecular level, and furnish data on micro twinning and defects occurring between crystalline domains. Cryo-T E M has been applied to elucidate the structure of 2-D and 3-D self-aggregates of amphiphilic alcohols, acids and their cadmium salts, bola-amphiphiles and mixed monolayers. Epitaxial crystallization of hexagonal ice underneath the monolayer of long chain alcohol was also directly demonstrated by this method.

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Study of mixed aggregates in aqueous solutions of sodium dodecyl sulfate and dodecyltrimethylammonium bromide

Cited by 79 publications

References 41 publications

Phase behaviour and structure of zwitanionic mixtures of perfluorocarboxylates and tetradecyldimethylamine oxide—dependence on chain length of the perfluoro surfactant

Phase behaviour and structure of zwitanionic mixtures of perfluorocarboxylates and tetradecyldimethylamine oxide—dependence on chain length of the perfluoro surfactant

Micellar catalysis in mixed anionic/cationic surfactant systems

Electron microscopy studies of amphiphilic self‐assemblies on vitreous ice

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