A F-19 NMR chemical shift study of a homologous series of perfluorocarbon (fc) [CxF2x+1CO2Na, x = 3, 4, 6-9] surfactants (S) has been carried out in D2O and in binary solvent (D2O + cyclodextrin (CD)) systems at 22 degrees C. Both beta-CD and modified cyclodextrins were used. Complementary H-1 NMR chemical shift data for the cyclodextrins in binary solvent (D2O + S) systems were also obtained. Values of the complex-induced chemical shifts (CIS) for selected host or guest nuclei are observed to increase with increasing alkyl chain (C-x) length of the surfactant when the CD/S complex has a 1:1 stoichiometry. However, for complexes having stoichiometries other than 1:1 CD/S, somewhat different trends in the CIS values were observed. Binding constants (K-i) have been obtained from the analysis of F-19 and H-1 CIS values of the CD/S systems using equilibrium models in which 1:1, 1:1 plus 2:1, 1:1 plus 1:2 complexes, and uncomplexed species are present. In general, K-i increases as C-x increases; however, differences in the binding affinity, stoichiometry, and inclusion geometry of the CD/S complexes mere observed to depend on the type of cyclodextrin. The latter can be understood in terms of the steric effects created by the introduction of alkyl groups in the annulus region of the cyclodextrin.