Formation of Microemulsions with Gemini-Type Surfactant.

Kunieda, H.; Kaneko, Masaya; Feng, Jia‐Xun; Tsubone, Kazuyuki

doi:10.5650/jos.51.761

Cited by 10 publications

(4 citation statements)

References 15 publications

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“…Hence, these hydrophilic nonionic groups tend to aggregate even in nonpolar media. Besides, the phase behavior of microemulsions in polyglycerol type nonionic surfactant systems is not largely influenced by temperature. − …”

Section: Introductionmentioning

confidence: 99%

Phase Behavior of Diglycerol Fatty Acid Esters−Nonpolar Oil Systems

et al. 2006

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Phase behavior of diglycerol fatty acid esters (Qn-D, where n represents the carbon number in the alkyl chain length of amphiphile, n = 10-16) were investigated in different nonpolar oils, liquid paraffin (LP70), squalane, and squalene. There is surfactant solid at lower temperature, and the surfactant solid does not swell in oil, and the melting temperature is almost constant in a wide range of compositions. In all of the systems, a lamellar liquid crystal (L(alpha)) is formed in a concentrated region at a temperature between the solid melting temperature and the isotropic two- or single-phase regions. In the dilute regions, reverse vesicles are formed in L(alpha) + O regions. There are two liquid-phase regions above the L(alpha) present region. This two-phase boundary corresponds to the cloud-point curve of nonionic surfactant aqueous solutions. However, instead of being less soluble in water at high temperature for the cloud point, the surfactant becomes more soluble in the organic solvents at high temperature. Namely, the effect of temperature on the solubility is opposite to the clouding phenomenon. When the hydrocarbon chain of the diglycerol surfactant decreases, the two-phase region becomes wider. In the case of a fixed surfactant, the surfactant is most miscible with squalene (narrowest two-phase regions) and the order of dissolutions tendency is squalene > LP70 > squalane. These results show that the hydrophilic moiety (diglycerol group) is more insoluble in oil compared with that of a conventional poly(oxyethylene)-type nonionic surfactant. Formation of reversed rodlike micelles was confirmed by SAXS scattering curve. When the hydrocarbon chain of surfactant is short, the micellar size becomes larger. In a fixed surfactant system, the reverse micellar size increases by changing oil from squalene to LP70. A small amount of water induces a dramatic elongation of reverse micelles.

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Section: Introductionmentioning

confidence: 99%

Phase Behavior of Diglycerol Fatty Acid Esters−Nonpolar Oil Systems

et al. 2006

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“…Hence, these hydrophilic, nonionic groups tend to aggregate even in nonpolar media, and it is possible to form different self-organized structures. Besides, the phase behavior in polyglycerol type nonionic surfactant systems is not largely influenced by temperature. − Polyglycerol fatty acid esters are the edible surfactants and mostly used in food, pharmacy, and cosmetics. Therefore an understanding of phase behavior study is of technological importance.…”

Section: Introductionmentioning

confidence: 99%

Phase Behavior of Monoglycerol Fatty Acid Esters in Nonpolar Oils: Reverse Rodlike Micelles at Elevated Temperatures

et al. 2006

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We have studied nonaqueous phase behavior and self-assemblies of monoglycerol fatty acid esters having different alkyl chain lengths in different nonpolar oils, namely, liquid paraffin (LP 70), squalane, and squalene. At lower temperatures, oil and solid surfactants do not mix at all compositions of mixing. Upon an increase in the temperature of the surfactant system, the solid melts to give isotropic single or two-liquid phases, depending on the nature of the oil and the surfactant. All monolaurin/oil systems form an isotropic single-phase liquid, but with a decreasing alkyl chain length of surfactant, they become less lipophilic and immiscible in oils. As a result, a two-phase domain is observed in the oil rich region of all monocaprylin/oil systems over a wide range of concentrations. Judging from the phase diagrams, the surfactants are the least miscible with squalane, and the order of miscibility tendency is squalene > LP 70 > squalane. With a further increase of temperature, the solubility of the surfactant in the oil increases, and the two-liquid phase transforms to an isotropic single phase. This phase transformation corresponds to the reverse of the cloud-point phenomenon observed in aqueous nonionic surfactant systems. Small-angle X-ray scattering (SAXS) measurements show the presence of reversed rodlike micelles in the isotropic single phase, and the length of the aggregates decreases with increasing temperature and increasing alkyl chain length of the surfactant. These results indicate a rod-sphere transformation with increasing lipophilicity of the surfactant and confirms the validity of Ninham's penetration model in the reversed system. An addition of a small amount of water dramatically enhances the elongation of the reverse micelles. Increasing the surfactant concentration or changing the oil from squalene to LP 70 also increases the length of the rodlike aggregates.

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“…In the past decade, new types of surfactants consisting of two hydrophobic and two hydrophilic groups connected by a flexible or rigid spacer chain in a molecule, called dimeric or gemini surfactants, have attracted considerable interests [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], because of their unique physicochemical properties such as lower critical micelle concentration (cmc), higher efficiency in reducing surface tension and better wetting ability than conventional monomeric surfactants [1,[17][18][19]. It has been shown that the cmc values of the gemini surfactants decrease unexpectedly when the number of carbon atoms in the hydrophobic chain exceeds a certain number, and this behavior is caused by the formation of small non-surfaceactive premicellar soluble aggregates [2,3,[8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Study on the Synthesis and Surface Active Properties of a Novel Surfactant with Triple Quaternary Ammonium Groups and Triple Dodecyl Chains Derived from Glycerin

Chen

Cui

2010

J Surfact & Detergents

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The new triple chain surfactant was firstly prepared by ring-opening and a quaternization reaction with 2-(chloromethyl)-oxirane, tertiary amine and propane-1,2,3-triol as starting materials. The surfactant was characterized by MS and elementary analysis. Air-Liquid surface tension was measured by using a tensiometer at temperatures from 298 to 318 K respectively and in various salt solutions (NaX). The results show that with the increase of temperature, the values of critical micelle concentration (cmc) can achieve a minimum at 308 K. The maximum surface adsorption capacity C decreases, while the minimum molecule A min area increases. With the increase in temperature and the decrease in counterionic diameter, the values of cmc decrease from 8.09 9 10 -5 to 5.52 9 10 -5 mol/L, and the adsorption capacity C increase from 1.80 9 10 -10 to 2.74 9 10 -10 mol/m 2 , while there are almost no influences to surface tension (c cmc ). The free energy of micelle formation is negative (-85.2 to -92.0 kJ/mol).

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Formation of Microemulsions with Gemini-Type Surfactant.

Cited by 10 publications

References 15 publications

Phase Behavior of Diglycerol Fatty Acid Esters−Nonpolar Oil Systems

Phase Behavior of Diglycerol Fatty Acid Esters−Nonpolar Oil Systems

Phase Behavior of Monoglycerol Fatty Acid Esters in Nonpolar Oils: Reverse Rodlike Micelles at Elevated Temperatures

Study on the Synthesis and Surface Active Properties of a Novel Surfactant with Triple Quaternary Ammonium Groups and Triple Dodecyl Chains Derived from Glycerin

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