A structural study of the mesophases of two oxyethylene alkyl ether-decane-water systems, a comparison between technical grade C12EO〈7〉 and pure C12EO6

Bouwstra, Joke A.; Jousma, H.; Meulen, M. M. van der; Vijverberg, C. C.; Gooris, G.S.; Spies, F.; Junginger, Hans E.

doi:10.1007/bf01416061

Cited by 19 publications

(15 citation statements)

References 15 publications

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“…Since only one peak was observed in the I 1 phase in the presence of oil, the detail structure is not identified. However, judging from the previous results and its positions in phase diagrams, the I 1 phase is considered to be body- or face-centered discrete cubic phase. ,, The type of liquid crystal was also identified by a polarizing microscope.…”

Section: Methodsmentioning

confidence: 99%

Effect of Oil on the Surfactant Molecular Curvatures in Liquid Crystals

1998

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The effect of added decane, m-xylene, or squalane on the phase behavior of the polyoxyethylene dodecyl ether (C12EO n ) −water system was investigated as a function of polyoxyethylene (EO) chain length at 25 °C. When the surfactant is relatively lipophilic (more lipophilic than the balanced state), the type of liquid crystal is changed to the more lipophilic one upon addition of decane. The lamellar (Lα) to lipophilic reverse hexagonal (H2) transition takes place in the C12EO3 system. On the other hand, the hexagonal (H1) to hydrophilic discrete cubic (I1) liquid crystal transition occurs in the hydrophilic C12EO7 system. There are two kinds of effects of oil on the self-organizing structures. One is the “penetration effect”, in which oil molecules penetrate into the surfactant palisade layer and expand the effective cross-sectional area, a S. The other is “swelling effect”, in which oil molecules are solubilized in the core of aggregates and expand the volume of aggregates. In this case, the a S is almost constant. Due to the swelling effect, the H1−I1 phase transition takes place in the decane−C12EO7 system, whereas the Lα−H2 transition occurs in the decane−lipophilic C12EO3 system due to the penetration effect. This causes the opposite tendency of the change in the curvature of the surfactant layers in liquid crystals on each side of the balanced state. As a result, the phase behavior of surfactant is quickly changed from forming micelles to reverse micelles within a narrow range of the EO chain in the presence of oil. On the other hand, m-xylene tends to penetrate the surfactant palisade layer, and the H1−Lα transition occurs even in the hydrophilic C12EO7 system.

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Section: Methodsmentioning

confidence: 99%

Effect of Oil on the Surfactant Molecular Curvatures in Liquid Crystals

1998

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“…Considering that the hexagonal phase is formed by cylindrical aggregates crystallized in a two-dimensional hexagonal lattice, geometrical relationships are used to derive the following equations relating the structural parameters d L and a s and the volume fractions φ Ls and φ La [12,13]: …”

Section: Small Angle X-ray Scattering (Saxs)mentioning

confidence: 99%

Phase diagrams and microstructure of aggregates in mixed ionic surfactant/foam booster systems

Rodríguez

Sakai

Fujiyama

et al. 2004

Journal of Colloid and Interface Science

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“…Considering that the hexagonal phase is formed by cylindrical aggregates crystallized in a two-dimensional hexagonal lattice, geometrical relations are used to derive the following equations relating the structural parameters r H and a s and the volume fractions φ Ls and φ La [17,18],…”

Section: The Phase Diagram Of the Cheo 15 /Nmea-12/ Water Systemmentioning

confidence: 99%