| Title
| - Neutron Small Angle Scattering Studies of Micellar Growth in Mixed Anionic-NonionicSurfactants, Sodium Dodecyl Sulfate, SDS, and Hexaethylene Glycol Monododecyl Ether,C12E6, in the Presence and Absence of Solubilized Alkane, Hexadecane
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| Abstract
| - Small angle neutron scattering, SANS, has been used to investigate the structure of mixed ionic−nonionicsurfactant micelles of SDS and C12E6. For solution compositions rich in C12E6, the evolution of micelle sizewith composition exhibits a pronounced maximum, in qualitative agreement with the theoretical predictionsof Shiloach and Blankschtein [Langmuir1998, 14, 7166], but with some important quantitative differenceswhich are discussed. The solubilization of the alkane, hexadecane, into the mixed surfactant micelle suppressesthe micelle growth with changing solution composition. For micelles rich in C12E6, hexadecane is solubilizedpredominantly into the palisade layer of the micelles, favoring small spherical micelles. The micellar growthwith changing solution composition arises from changes in the balance between the headgroup and stericcontributions to the free energy of micellization, and the addition of alkane further alters that balance infavor of small spherical micelles.
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