PULSED-FIELD GRADIENT SPIN-ECHO NMR EXPERIMENTS IN MICELLAR SOLUTIONS OF 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-diffusion coefficients in the micellar solution of the system cetyltrimethylammonium bromide/water. These results have been supported by those obtained by NMR experiments performed with a Fourier Transform spectrometer. The water selfdiffusion coefficients were used to calculate the obstruction effect of the micellar aggregates in accordance with a stoichiometric model already used for lyotropic mesophases. It was found that the micellar aggregates change shape with the concentration and are characterized by an average hydration number of approximately 9 +/- 3.