Aqueous microemulsions of a fluorinated surfactant and oil studied by PFG-NMR: transformation from threadlike to spherical micelles.
The aqueous microemulsion system consisting of the fluorinated surfactant tetraethylammonium perfluorooctylsulfonate (TEAFOS) and the fluorinated oil 1H-perfluorohexane (PFH) has been investigated using the pulsed field gradient NMR self-diffusion method on both 1H and 19F. Neat TEAFOS(aq) builds threadlike micelles from rather low surfactant concentrations up to ca. 80 mmol kg(-1). The addition of PFH to TEAFOS(aq) solutions induces a transition from threadlike micelles to spherical micelles solubilizing the oil. In this paper, information from the self-diffusion coefficients of oil (PFH), surfactant counterion (TEA+), surfactant ion (FOS-), and water (HDO) during the transition is presented.
Johannessen
Espen
E
Graduate School of Materials Research, Department of Physical Chemistry, Abo Akademi University, FI-20500 Abo, Finland. espen.johannessen@abo.fi
Walderhaug
Harald
H
Balinov
Balin
B