PULSED-FIELD GRADIENT SPIN-ECHO NMR EXPERIMENTS IN MICELLAR SOLUTIONSOF THE WATER CETYLTRIMETHYLAMMONIUM BROMIDE SYSTEM

Pulsed Field Gradient NMR experiments, in their original time domain, have been carried out to separate both water and surfactant self-diffu sion coefficients in the micellar solution of the system cetyltrimethy lammonium bromide/water. These results have been supported by those ob tained by NMR experiments performed with a Fourier Transform spectrome ter. The water selfdiffusion coefficients were used to calculate the o bstruction effect of the micellar aggregates in accordance with a stoi chiometric model already used for lyotropic mesophases. It was found t hat the micellar aggregates change shape with the concentration and ar e characterized by an average hydration number of approximately 9 +/- 3.