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  • Rod-like micelle  (1)
  • Sucrose monoalkanoate  (1)
  • ion-pairedsurfactant  (1)
  • 1
    ISSN: 1435-1536
    Keywords: Rod-like micelle ; cationicfluorocarbon surfactant ; dynamiclightscattering ; electricbirefringence ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The micellar properties of a cationic fluorocarbon surfactant, diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMAC), are studied by surface tension, fluorescence of pyrene-3-carboxaldehyde (PCA), and electric conductivity measurements. These measurements indicate that DEFUMAC solution provides a low surface tension and that its micelles present higher polar conditions under PCA than do cationic hydrocarbon surtactant micelles. Moreover, the micellar elongation induced by increasing concentrations of salt and surfactant concentration is observed by use of dynamic light scattering, transient electric birefringence, and viscosity measurements. The elongation by addition of salt can be explained by a multiple equilibrium description, while the elongation by increasing surfactant concentration is rapid above a particular concentration, viz. second CMC. Consequently, DEFUMAC micelle elongates more rapidly than do corresponding cationic hydrocarbon surfactants with chloride counterion.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 273 (1995), S. 584-589 
    ISSN: 1435-1536
    Keywords: Sucrose monoalkanoate ; lamellar liquid crystal ; small-angle x-ray scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Phase diagram of a water/sucrose monododecanoate (SE)/hexanol system was determined at 30°C. Aqueous micellar, reverse micellar, normal hexagonal liquid crystalline, and lamellar liquid crystalline phases appear in the phase diagram. The change in interlayer spacing and interfacial section area of surfactant in the liquid crystalline phases was investigated by small-angle x-ray scattering. Upon addition of water, the section area and the radius of cylindrical aggregates are almost constant in a hexagonal liquid crystal, whereas the distance between each cylinder is separated on the water-SE axis. The interlayer spacing slightly decreases or is almost unchanged on the surfactant-hexanol axis, because alcohol molecules penetrate into the palisade of bilayers. Although the average section area decreases with increasing alcohol content, each section area of SE and alcohol molecules are kept constant. Since the interfacial section area of alcohol is less than the section area of hydrocarbon chain, the phase transition from lamellar liquid crystal to reverse micelle occurs in an alcohol-rich region.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1536
    Keywords: Fluorocarbonsurfactant ; mixedsystem ; ion-pairedsurfactant ; P β phase ; lamellarphase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Two ternary phase diagrams of the cationic perfluorosurfactant diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMAC) with an anionic perfluorosurfactant lithium perfluorooctanesulfonate (LiFOS) and an anionic hydrocarbon surfactant lithium dodecyl sulfate (LiDS) have been established at 25°C. The total surfactant concentration was less than 20wt%. In a wide mixing region of the LiFOS/DEFUMAC system, a lamellar-type phase,P β, was identified by its texture under a polarization microscope and by its x-ray diffraction pattern. Dispersed fragments ofP β-phase are present in the dilute solutions in which one surfactant was in excess. The anisotropy of electrical conductivity, flow birefringence, dynamic light scattering, and electric briefringence demonstrate that theP β fragments are disk-like with a radius of 0.7 μm. The disk-likeP β particles are transformed by shear into a spherical aggregate ofL α above a critical shear gradient. LiDS/DEFUMAC mixed solution forms dispersed and precipitatedL α in the dominant region. Radius and micropolarity of the dispersedL α aggregates are decreased as the ratio of LiDS:DEFUMAC approaches 1:1. On the basis of x-ray diffraction measurement the structure of precipitatedL α-phase seems to consist of monolayers.
    Type of Medium: Electronic Resource
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