The self-assembly of polymeric worm-like micelles in water was studied by rheology, light scattering and small angle neutron scattering. The polymer was synthesized by randomly grafting pendant quaternized alkylamine moieties to a polystyrene chain. The rheological properties of the gels evolve greatly over time: the elastic modulus G' increases up to a maximum and then decreases. It is possible to obtain a kinetic master curve of evolution of the G' at different temperatures. Structural measurements show the presence of heterogeneities that disappear slowly in time or when the samples are heated.