  The catanionic system didodecyldimethylammonium bromide (DDAB)- sodium
taurodeoxycholate (STDC)-D2O is characterized by an exceptionally extended L1
region. The comparison of self-diffusion coefficient of the solvent and the
DDAB embedded in the micelles provided information about hydration of the
aggregates. Moreover, correlating self-diffusion and 14N NMR relaxation
measurements new insight could be obtained regarding the translational and
rotational micellar motions in the crowded solutions of systems with 0.2
DDABSTDC molar ratio. 1H 2D NMR spectra gave some hints about the mutual
arrangement of DDAB and STDC within the aggregates. For samples with 1.8 and
2.6 DDAB/STD molar ratios the 14N data were in agreement with the presence of
somewhat branched, interconnected micelles. 23Na and 81Br dynamic parameters
resulted particularly sensitive to the surrounding environment. The peculiar
rheological behaviour of the, highly concentrated, branched micelles samples,
namely the steady oscillations in the step tests, was found to be an example of
instability originated by the combined effect of material elasticity and
slippage at the fixed wall.
