This proposal concerns the kinetic of formation/dissolution of micellar aggregates in oppositely charged polyelectrolyte/surfactant systems by time resolved SANS experiments. The average structure of these complexes results from the subtle balance between hydrophilic, hydrophobic and ionic interactions. It can be viewed as a pearlnecklace in which the polyion decorates micellar aggregates.We propose to focus on NaPSS/DOTAB complexes using a stopped-flow apparatus and to measure the modifications of the scattering patterns as a function of time after a rapid change in solution composition.