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  • 1
    Electronic Resource
    Electronic Resource
    The sphere-rod transition of micelles of dodecyldimethylammonium bromide in aqueous NaBr solutions, and the effects of counterion binding on the micelle size, shape and structure (1984)
    Springer
    Colloid & polymer science 262 (1984), S. 409-417 
    Details
    ISSN: 1435-1536
    Keywords: dodecyldimethylammonium bromide ; rodlike micelle ; light scattering ; counter ion binding ; micelle size
    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 Micelle size and shape of dodecyldimethylammonium bromide have been determined by measurement of light scattering from its aqueous NaBr solutions. In water and in the presence of NaBr up to 0.07 M, the Debye plots give straight lines with positive slopes, and spherical micelles having molecular weight less than 30 000 are formed. At higher NaBr concentrations, the Debye plots decrease with increasing micelle concentration, indicating the aggregation of the primary spherical micelles into larger secondary micelles. The molecular weight and the radius of gyration of the secondary micelles increase with increasing NaBr concentration, and the relation between molecular weight and radius of gyration suggests that they are rodlike and flexible. Linear logarithmic relations between micelle molecular weight and ionic strength hold for spherical and rodlike micelles, respectively, and the threshold concentration of NaBr for the sphere-rod transition is located at 0.07 M. The spherical micelle of dodecyldimethylammonium ions has a size more than 20 surfactant ions larger in NaBr solutions than in NaCl solutions, and their rodlike micelle has a shorter length in NaBr solutions than in NaCl solutions, when compared at an identical aggregation number, indicating 2 more surfactant ions in its cross-section.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410261
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  • 2
    Electronic Resource
    Electronic Resource
    Formation of rodlike micelles of dimethyloleylamine oxide in aqueous solutions: effects of addition of HCl and NaCl on the micelle size and the intermicellar interaction (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 756-766 
    Details
    ISSN: 1435-1536
    Keywords: Light scattering ; dimethyloleylamine oxide ; rodlike micelle ; wormlike chain ; external interference
    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 Angular dependence of light scattering has been measured for aqueous solutions of dimethyloleylamine oxide in the presence of HCl and NaCl. In micellar solutions more concentrated than 0.1×10−2 g cm−3, rodlike micelles are dominantly formed, and their properties are strongly reflected in the characteristics of the solutions. The aggregation number, radius of gyration and even flexibility of the rodlike micelles increase with the addition of HCl as well as NaCl. The increase of HCl concentration up to 10−3 N makes the aggregation number of rodlike micelles as large as 58,000, when 0.01 M NaCl is present. The large micelle size would be stabilized by the dehydration of the amine oxide group and the hydrogen bonding between nonprotonated and protonated molecules in a micelle. In aqueous solutions without HCl and NaCl or in their presence at very low concentrations, the light scattering is subject to the effects of both external and internal interferences. The effect of external interference can be separated from the effect of internal interference by applying the Zernike-Prins equation to the observed angular dependence of light scattering. Then the second virial coefficient and the pair interaction potential of rodlike micelles can be derived by means of certain approximate methods. The addition of HCl to 10−3 N makes both repulsive and attractive forces stronger and the resulting potential well deeper, but the addition of NaCl depresses such an effect of HCl considerably.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422859
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  • 3
    Electronic Resource
    Electronic Resource
    Solubilization properties of aqueous solutions of alkyltrimethylammonium halides toward a water-insoluble dye (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 637-645 
    Details
    ISSN: 1435-1536
    Keywords: Solubility ; solubilization power ; Sudan Red B ; alkyltrimethylammonium halide ; rodlike micelle
    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 solubility of a water-insoluble dye, Sudan Red B, in aqueous sodium halide solutions of tetradecyl-, cetyl-, and stearyltrimethylammonium halides has been measured at different surfactant and salt concentrations, and the dependence of solubilization properties on alkyl chain length has been discussed with reference to the micelle size and shape. At low ionic strengths where only spherical micelles exist, the solubilization power of micellar surfactant slightly increases with increasing the ionic strength, but it sharply increases at high ionic strengths above the threshold value of sphere-rod transition. However, the solubilization power becomes independent of the ionic strength, if their rodlike micelles are sufficiently long. The solubilization capacity increases linearly with increasing the molecular weight, almost independent of counterion species, but the rod-like micelle has a higher solubilization capacity than the spherical micelle. The solubilization capacity is larger for a surfactant with longer alkyl chain, indicating that the dye is solubilized more readily in a larger hydrophobic core. The solubilized dye is situated in a rodlike micelle of alkyltrimethylammonium halides, on average, 4.5–7.5 nm apart from each other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412780
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