Cloud point phenomena in mixtures of anionic and cationic surfactants in aqueous solution

Nakama, Yasunari; Harusawa, Fuminori; Murotani, I.

doi:10.1007/bf02540478

Cited by 20 publications

(23 citation statements)

References 12 publications

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“…For catanionic surfactants, a combination of straight FC-chains is likely to promote growth of disk-like micelles with an increasing energy difference. [23][24][25][26] Taken together, these results showing formation of disk-like micelles in water implies the catanionic surfactants have sufficiently high CPP values suitable for forming reverse micelles. In addition, the low CMC values < 1 mM and very low γ CMC of 13.5-16.8 mN/m suggests a low HLB and high surface activity of these catanionic surfactants.…”

Section: Effects Of Catanionic Surfactant Structure On Interfacial Prmentioning

confidence: 64%

“…Considering both nFG(EO) 2 and [C 6 F 13 mim][C 6 F 13 S] to be di-FC-chain surfactant molecules, differences in CPP and/or aggregation number are likely to come from the headgroup structure and interactions, i.e. electrostatic interactions between the anionic and catanionic headgroups, respectively [23][24][25][26][27][28][29][30]. Conclusions W/CO 2 microemulsions (W/CO 2 μEs) are potential universal green-solvents having both polar and nonpolar solvent properties, which can be used for various chemical applications as mentioned in the Introduction 2,3.…”

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confidence: 99%

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Water-in-CO₂ Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs

et al. 2019

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High-water-content water-in-supercritical CO2 (W/CO2) microemulsions are considered to be green, universal solvents, having both polar and nonpolar domains. Unfortunately, these systems generally require environmentally unacceptable stabilizers like long and/or multifluorocarbon-tail surfactants. Here, a series of catanionic surfactants having more environmentally friendly fluorinated C4–C6 tails have been studied in terms of interfacial properties, aggregation behavior, and solubilizing power in water and/or CO2. Surface tensions and critical micelle concentrations of these catanionic surfactants are, respectively, lowered by ∼9 mN/m and 100 times than those of the constituent single fluorocarbon-tail surfactants. Disklike micelles in water were observed above the respective critical micelle concentrations, implying the catanionic surfactants have a high critical packing parameter, which should be suitable for the formation of reverse micelles. Based on visual observation of phase behavior and Fourier transform infrared spectroscopic and small-angle neutron scattering studies, one of the three catanionic surfactants tested was found to form transparent single-phase W/CO2 microemulsions with a water-to-surfactant molar ratio of up to ∼50. This is the first successful demonstration of the formation of W/CO2 microemulsions by synergistic ion-pairing of anionic and cationic single-tail surfactants. This indicates that catanionic surfactants offer a promising approach to generate high-water-content W/CO2 microemulsions.

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Section: Effects Of Catanionic Surfactant Structure On Interfacial Prmentioning

confidence: 64%

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confidence: 99%

Water-in-CO₂ Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs

et al. 2019

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“…Finally, if very strong interactions occur between the two surfactants, such as those found in anionic-cationic and some zwitterionic-ionic mixtures, a double eutectic may be exhibited separated by a maximum in the Krafft temperature (182,183). Such behavior in non-amphiphilic systems is indicative of compound formation, suggesting that an analogous situation occurs in the above mixed surfactant systems.…”

Section: Precipitation Temperatures In Surfactant Mixtures When a Sumentioning

confidence: 96%

Mixed Surfactant Systems

Holland¹,

Rubingh

1992

Mixed Surfactant Systems

251

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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“…The surface and bulk properties of aqueous solutions of oppositely charged surfactants and those of ionic and nonionic surfactants are often greater than expected for the other types of mixed systems. Mixed systems composed of anionic and cationic surfactants (15)(16)(17)(18)(19) often result in strong coulombic interaction with remarkably lower CMC in mixtures than expected for ideal mixing. This deviation from ideal behavior was successfully explained by Rubingh (20) using the phase separation model of micellization and regular solution approximation.…”

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Mixed micelles of cationic surfactants and bile acid salts in aqueous media

George

Vora

Dogra

et al. 1998

J Surfact & Detergents

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Critical micelle concentrations of cetyltrimethylammonium-p-toluene sulfonate (CTAT) and cetylpyridinium chloride (CPC) with sodium cholate (NaC) and sodium deoxycholate (NaDC) were determined in aqueous solutions by surface tension measurements. Interaction parameters and mole fraction of the components in mixed micelles were estimated using Rubingh's theory. Strong interaction was observed for each mixed system, a common feature shown by anionic-cationic mixtures. Dramatic effects on the viscosities of these cationic surfactant-bile salt mixtures were seen, and were markedly dependent upon the counterion of the cationic surfactant and the nature of bile salts. Micelles are small and spherical for cationic surfactants in the presence of NaC. Micelle growth was seen for CPC in the presence of NaDC by an increase in viscosity, but a CTAT solution showed an opposite effect on addition of NaDC. Conductance results supported this view. Different behavior of the two bile salts is explained on the basis of their orientation in cationic micelles. JSD 1, 507-514 (1998). KEY WORDS:Ideal mixing, interaction parameter, mixed micelles, sodium cholate, sodium deoxycholate, synergism.Recently, much interest has been expressed in studying mixed surfactant systems both from basic and applied viewpoints (1,2). Usually, a marked interaction is observed, resulting in an increased cloud point, decreased Krafft point, increased surface activity, and decreased critical micelle concentration (CMC). Each change contributes favorably to practical applications of surfactants. Superiority in the performance of surfactant mixtures compared to single pure surfactants is often attributed to synergistic interactions among surfactants (1). Much research has focused on mixed systems comprised of anionic-anionic (3-6), cationic-cationic (7,8), anionic-cationic (9,10), ionic-nonionic (11), and nonionic-nonionic (12,13) surfactants. The CMC of surfactant mixtures composed of similarly structured ionic surfactants (14) or nonionic surfactants (14) can be predicted by assuming that they obey ideal solution theory in the micellar phase. The surface and bulk properties of aqueous solutions of oppositely charged surfactants and those of ionic and nonionic surfactants are often greater than expected for the other types of mixed systems. Mixed systems composed of anionic and cationic surfactants (15-19) often result in strong coulombic interaction with remarkably lower CMC in mixtures than expected for ideal mixing. This deviation from ideal behavior was successfully explained by Rubingh (20) using the phase separation model of micellization and regular solution approximation. However, in most cases the complex formed is generally insoluble in water (increased Krafft point), limiting the studies and applications of such systems. Although for anionic-cationic combinations a high probability of precipitation through charge neutralization at comparable ratio is present, when one component is in excess, stable mixed micelles are generally formed (21,22).Bile ...

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Cloud point phenomena in mixtures of anionic and cationic surfactants in aqueous solution

Cited by 20 publications

References 12 publications

Water-in-CO₂ Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs

Water-in-CO₂ Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs

Mixed Surfactant Systems

Mixed micelles of cationic surfactants and bile acid salts in aqueous media

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Cloud point phenomena in mixtures of anionic and cationic surfactants in aqueous solution

Cited by 20 publications

References 12 publications

Water-in-CO2 Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs

Water-in-CO2 Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs

Mixed Surfactant Systems

Mixed micelles of cationic surfactants and bile acid salts in aqueous media

Contact Info

Product

Resources

About

Water-in-CO₂ Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs

Water-in-CO₂ Microemulsions Stabilized by Fluorinated Cation–Anion Surfactant Pairs