The micellar structures formed by the perfluorooctylsulfonate ion (FOS-) in combination with the tetraethylammonium (TEA(+)) and lithium (Li+) counterions are studied by measuring the NMR chemical shifts and self-diffusion coefficients of both TEA(+) and FOS- at 30 degrees C. Spherical micelles generated by LiFOS are characterized by a lifetime of 10(-6) s, an aggregation number of about 36, and a cmc value of 7.16 mM. The fluorine spectrum of the FOS- ion in the micellar solutions of LiFOS consists of one set of peaks whose chemical shifts are averaged between the monomer and micellar states. When combined with the hydrophobic TEA(+) counterion, the FOS- ions show the F-19 spectra which consist of two sets of peaks whose chemical shifts and intensities are concentration dependent. The F-19 spectroscopic features are discussed by assuming the appearance of small aggregates at high surfactant concentrations. The binding coefficient (0.80) of the TEA(+) counterions to FOS-micelles is determined on the basis of the self-diffusion coefficients, measured for both TEA(+) and FOS-, The micellar self-diffusion coefficient in the TEAFOS system (8.4 x 10(-12) m(2) s(-1)) is found to be 1 order of magnitude lower than that in LiFOS system (5.7 x 10(-11) m(2) s(-1)), reflecting the s dynamic slowdown due to the formation of threadlike micelles.