We report on a small angle neutron scattering (SANS) study of self-organization of a novel triblock copolymer containing a crystalline poly(ethylene terephthalate) oligomer, a rubbery poly(lauryl acrylate) midblock, and a polyelectrolyte block (quaternized poly(2-(dimethylamino)ethyl methacrylate)) of various length. The rheology of the solutions showed a transition from Newtonian flow at low concentrations, to shear-thinning at intermediate concentrations, and finally a yield behavior at high concentrations. The microstructure of the samples investigated by SANS was found to evolve strongly with the polyelectrolyte block length. The data were analyzed in terms of aggregation numbers, radius of gyration, and aggregate hydration. Complete modeling of the intensity curves was achieved by an inversion method extracting an average aggregate radial volume fraction profile. In both rheology and microstructure, a surprising strong impact of the small PET block was observed.