H-1 and C-13 NMR studies of mixed counterion, cetyltrimethylammonium bromide cetyltrimethylammonium dichlorobenzoate, surfactant solutions: The intercalation of aromatic counterions

One- and two-dimensional H-1 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 H-1 NMR studies of the N-CH3 and the alpha-CH2 through epsilon-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. C-13 chemical shifts for the carbonyl carbons of the dichlorobenzoate counterions in their respective micellar systems also support this assertion.