1H and 13C NMR Studies of Mixed Counterion, Cetyltrimethylammonium Bromide/Cetyltrimethylammonium Dichlorobenzoate, Surfactant Solutions:  The Intercalation of Aromatic Counterions

One- and two-dimensional 1H NMR studies of mixed counterion CTAB/CTA3,5 and CTAB/CTA2,6 surfactant systems indicate that, in their respective micelles, the dichlorobenzoate counterions intercalate among the surfactants' trimethylammonium headgroups. Shielding effects observed in 1D 1H NMR studies of the N−CH3 and the α-CH2 through ε-CH2 protons suggest that, on average, the 3,5-dichlorobenzoate counterions insert further into the interface of their rodlike micelles than the 2,6-dichlorobenzoate counterions insert into the interface of their spherical micelles. 13C chemical shifts for the carbonyl carbons of the dichlorobenzoate counterions in their respective micellar systems also support this assertion.