Catanionic surfactant films at the air–water interface

Wang, Yujie; Pereira, Carlos M.; Marques, Eduardo F.; Brito, Rodrigo O.; Ferreira, Elisabete S.C.; Silva, A. Fernando

doi:10.1016/j.tsf.2006.04.044

Cited by 19 publications

(25 citation statements)

References 45 publications

(50 reference statements)

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“…Based on the isotherms obtained at different temperatures, one may conclude that the mixed DTMAB-SDS monolayer progressively dissolved into the aqueous subphase upon the interface compression. In addition, small monolayeroccupied areas at the onset of a detectable surface pressure and low surface pressures attained by interface compression have been reported for monolayers composed of catanionic surfactants, dodecyltrimethylammonium-dodecyl sulfate and dodecylammonium-dodecyl sulfate, and have been considered as typical characteristics of a soluble monolayer at the air/water interface [22].…”

Section: Mixed Surfactants With Same Alkyl Chain Lengthmentioning

confidence: 99%

“…Some researchers have studied the monolayer characteristics by spreading complex aggregates formed from equimolar mixing of oppositely charged surfactants with removal of inorganic counterions [20][21][22]. The Langmuir monolayer behavior of the complexes formed from cetylpyridinium chloride with sodium alkyl sulfate or sulfonate has been studied by Kang et al [20], and the alkyl chain length effect of the anionic surfactants on the Langmuir monolayer behavior has been discussed.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the effects of length and number of surfactant hydrocarbon chains on the phase behavior and molecular organization of the spread catanionic monolayers at the air/water interface have been discussed with the consideration of the molecular desorption from the monolayers [22].…”

Section: Introductionmentioning

confidence: 99%

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Phase behavior and morphology of equimolar mixed cationic–anionic surfactant monolayers at the air/water interface: Isotherm and Brewster angle microscopy analysis

Chou

Lin

et al. 2008

Journal of Colloid and Interface Science

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Section: Mixed Surfactants With Same Alkyl Chain Lengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phase behavior and morphology of equimolar mixed cationic–anionic surfactant monolayers at the air/water interface: Isotherm and Brewster angle microscopy analysis

Chou

Lin

et al. 2008

Journal of Colloid and Interface Science

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“…There is a large body of experimental information available [10][11][12][13][14][15] that shows that the dynamic and equilibrium properties of the resulting interfaces are also very much dependent on the branching and chain lengths of the hydrophobic segments of the individual surfactants. In contrast, from the theoretical side, the information available on these complex mixtures is not that abundant and have mainly focused on predictions of their thermodynamic properties based on classical theories of liquid mixtures.…”

Section: Introductionmentioning

confidence: 99%

Computer simulations of catanionic surfactants adsorbed at air/water interfaces. II. Full coverage

Clavero

Rodríguez

Laría

2007

The Journal of Chemical Physics

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We extend our previous molecular dynamics experiments ͓Rodriguez et al., J. Phys. Chem. B 109, 24427 ͑2005͔͒ to the analysis of the adsorption of catanionic surfactants at water/air interfaces, at a surfactant coverage close to that of the saturated monolayer: 30.3 Å 2 per headgroup. The mixture of surfactants investigated corresponds to equal amounts of dodecytrimethylammonium ͑DTA͒ and dodecylsulfate ͑DS͒. The structure of the interface is analyzed in terms of the local densities and orientational correlations of all relevant interfacial species. In accordance with experimental evidence, the DTA headgroups penetrate deeper into the aqueous substrate than the DS ones, although the average positions of all headgroups, with respect to the interface, lie in positions somewhat more external than the ones observed at lower coverages. Average tail tilts are close to 45°. The characteristics of the headgroup-water substrate correlations are also analyzed using a tessellation procedure of the interface. The density and polarization responses of the interfacial domains closest to the DS headgroups are enhanced, compared to those adjacent to the DTA detergents. Dynamical aspects related to the diffusion and to the orientational correlations of different water layers in close contact with the surfactant are also investigated.

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“…相反电荷的混合表面活性剂体系, 由于极性头之间强的静电引力, 在一定浓度区间表现为较强的协同效应 [14,16,18,24,27] . 从微观角度讲, 由于正负电荷的中和, 极性头的表观亲水性降低, 表观截面积明显减小 [28,29] . 因此, 其比单一表面活性剂有更丰富的聚集形态, 包括球形、椭球形、棒状和纤维状胶束, 在适当的组成和浓度区域形成液晶如层状液晶和囊泡等 [13,14,18] .…”

Section: 引言unclassified

Thermodynamics of interaction between two kinds of surfactants with asymmetric hydrophobic moieties of alkyl tail and rigid face

et al. 2014

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In this work, the thermodynamics of molecular self-assembly for an anionic biosurfactant, sodium deoxycholate (NaDC) and their mixture with an oppositely charged surfactant, docecyltrimethylamonium bromide (DTAB) in aqueous solution was investigated by isothermal titration calorimeter (ITC), companied with turbidity and conductivity measurements. From the perspective of interaction energy, the results for single surfactant NaDC obtained from ITC provided a direct evidence for the stepwise association model to form the premicelles in the first step and the stable micelles in the second step. We obtained a series of thermodynamic parameters of premicellar and micellar formation, and thus discussed the thermodynamic mechanisms of molecular aggregation in these two processes. Furthermore, we investigated the thermodynamics of intermolecular interaction for the mixed systems composed of oppositely charged surfactants (DTAB/NaDC). The mixed critical micelle concentration (cmc mix ) and the transition concentration between two micellar morphologies (C M ) and their corresponding changes of enthalpy in the both processes were derived from ITC measurements in rich-NaDC and in rich-DTAB region, respectively. The results show that aggregation behaviors of DTAB/NaDC differ from single surfactant system or the normal mixed surfactants with charged "head-and-tail", due to the asymmetry in molecular structures caused by the rigid steroid skeleton of NaDC composed of a hydrophilic and a hydrophobic surfaces. As a result, the occurrence of various aggregation processes in mixed solution can be controlled by the total concentrations of two surfactants and their molar ratio. Conclusively the process of mixed micellization is driven by entropy, and the transition between two kinds of micellar morphologies is driven jointly by entropy and enthalpy. Therefore, from the perspective of interaction themodynamics, this work gave a deep insight in understanding the themodynamics of molecular selfassembly and their phase behavior for mixed systems with bile salts and the positively charged surfactant.

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Catanionic surfactant films at the air–water interface

Cited by 19 publications

References 45 publications

Phase behavior and morphology of equimolar mixed cationic–anionic surfactant monolayers at the air/water interface: Isotherm and Brewster angle microscopy analysis

Phase behavior and morphology of equimolar mixed cationic–anionic surfactant monolayers at the air/water interface: Isotherm and Brewster angle microscopy analysis

Computer simulations of catanionic surfactants adsorbed at air/water interfaces. II. Full coverage

Thermodynamics of interaction between two kinds of surfactants with asymmetric hydrophobic moieties of alkyl tail and rigid face

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