Formation of Cubic-Phase Microemulsions with Anionic and Cationic Surfactants at Equal Amounts of Oil and Water

Li, Xingfu; Kunieda, H.

doi:10.1006/jcis.2000.7128

Cited by 14 publications

(9 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When 2 to 4 wt% hexanol was introduced into the SDS-DPCl systems, stable middlephase microemulsions formed for TCE, hexane, and n-hexadecane (data not shown). This is consistent with the work of others, and our discussion of interaction forces above, which showed that alcohol addition is necessary to avoid these structured phases (9)(10)(11)29). Since our goal was to develop mixed cationic-anionic surfactant systems capable of forming middle-phase microemulsions without alcohol addition, SDS-DPCl systems were not further evaluated.…”

Section: Resultssupporting

confidence: 90%

“…Research on the solubilization and phase behavior of microemulsions using mixed anionic and cationic surfactants has found that alcohol addition is generally necessary to avoid liquid crystal formation and thus form middle-phase microemulsions (9)(10)(11). When alcohol is used, mixed anionic and cationic surfactant systems have produced ultra-low IFT and maximal solubility enhancement consistent with optimal middle-phase microemulsion (9)(10)(11). Lindman and co-workers (12,13) investigated the phase behavior of microemulsions with an anionic and a cationic surfactant in equimolar ratios without electrolyte addition.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Formulating middle‐phase microemulsions using mixed anionic and cationic surfactant systems

Doan¹,

Acosta²,

Sabatini³

2003

J Surfact & Detergents

View full text Add to dashboard Cite

Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase behavior was studied for three anionic-cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane, and n-hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed us to form alcohol-free middle-phase microemulsion using mixed anionic-cationic systems (i.e., liquid crystals did not form). The anionic to cationic molar ratio required to form middle-phase microemulsions approached 1:1 for univalent surfactants as oil hydrophobicity increased (i.e., TCE to hexane to n-hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic-cationic surfactant mixtures in surfactant-enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the oil was extracted in 2.5 pore volumes using an anionic-rich surfactant system. By contrast, cationic-rich systems performed very poorly (<1% oil removal), reflecting significant losses of the cationic-rich surfactant system in the porous media. The results thus suggest that, when properly designed, anionic-rich mixtures of anionic and cationic surfactants can be efficient for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures advantageous.Mixed anionic-cationic surfactant systems. Mixtures of anionic and cationic surfactants often exhibit synergistic effects. The synergism depends on the charge and molecular structure of the individual surfactant components and can be attributed to nonideal mixing effects, which can produce substantially lower critical micelle concentration CMC values and interfacial tensions (IFT) than otherwise possible (1). For anioniccationic surfactant mixtures, the mixed CMC can be two orders of magnitude below that expected if the surfactants have similar structure (2). The use of mixed anionic and cationic surfactants has been evaluated in washing and fabric softening, analytical chemistry, enhanced oil recovery, and pharmaceutical applications (3-5).In this project we are particularly interested in the use of anionic-cationic surfactant mixtures in the formulation of microemulsions. Microemulsions are optically transparent, thermodynamically stable phases containing oil and water stabilized by an interfacial film composed of surfactants and sometimes other molecules (e.g., cosurfactant, alcohols). Microemulsions are important in many applications such as enhanced oil recovery, remediation of oil-impacted aquifer, detergency,...

show abstract

Section: Resultssupporting

confidence: 90%

mentioning

confidence: 99%

Formulating middle‐phase microemulsions using mixed anionic and cationic surfactant systems

Doan¹,

Acosta²,

Sabatini³

2003

J Surfact & Detergents

View full text Add to dashboard Cite

show abstract

“…Strikingly, choline soaps even show two distinct I 1 phases in water, which has previously only been reported for non-ionic, 35,60 zwitter-ionic 33 and divalent surfactants.…”

Section: 1315mentioning

confidence: 60%

Aqueous phase behaviour of choline carboxylate surfactants—exceptional variety and extent of cubic phases

et al. 2011

View full text Add to dashboard Cite

Choline carboxylate surfactants are powerful alternatives to the well-known classical alkali soaps, since they exhibit substantially increased water solubility while maintaining biocompatibility, in contrast to simple quaternary ammonium ions. In the present study, we report the aqueous binary phase diagrams and a detailed investigation of the lyotropic liquid crystalline phases formed by choline carboxylate surfactants (ChCm) with chain lengths ranging from m ¼ 12-18 and at surfactant concentrations of up to 95-98 wt%. The identification of the lyotropic mesophases and their sequence was achieved by the penetration scan technique. Structural details are elucidated by small-angle X-ray scattering (SAXS). The general sequence of mesophases with increasing soap concentration was found to be as follows: micellar (L 1 ), discontinuous cubic (I 1 ), hexagonal (H 1 ), bicontinuous cubic (V 1 ) and lamellar (L a ). The main difference to the phase behavior of alkali soaps or of other mono-anionic surfactants is the appearance and large extent of a discontinuous cubic phase with two or even more different symmetries. The obtained phase diagrams further highlight the extraordinarily high water solubility of ChCm soaps. Finally, structural parameters of ChCm salts such as the cross-sectional area at the polarnonpolar interface are compared to those of alkali soaps and discussed in the terms of specific counterion binding and packing constraints.

show abstract

“…In many respects, liquid crystals behave as fluids, even though they possess more ordered structures than ordinary liquids. Cryo-TEM and small-angle X-ray scattering (SAXS) are the primary tools for the structural studies of liquid crystals [96][97][98][99][100][101]. The basic building blocks of the bicontinuous cubic phase are the lipid bilayers contorted into the shape of infinite periodic minimal surfaces.…”

Section: A Review Of Experimental Studies On the Dynamics And Structumentioning

confidence: 99%

Interfacial dynamics and structure of surfactant layers

Zhmud¹,

Tiberg

2005

Advances in Colloid and Interface Science

View full text Add to dashboard Cite

Formation of Cubic-Phase Microemulsions with Anionic and Cationic Surfactants at Equal Amounts of Oil and Water

Cited by 14 publications

References 36 publications

Formulating middle‐phase microemulsions using mixed anionic and cationic surfactant systems

Formulating middle‐phase microemulsions using mixed anionic and cationic surfactant systems

Aqueous phase behaviour of choline carboxylate surfactants—exceptional variety and extent of cubic phases

Interfacial dynamics and structure of surfactant layers

Contact Info

Product

Resources

About