In the present work, we suggest a novel method for obtaining interpolyelectrolyte complex (IPEC) by free radical polymerization in water–salt dispersions of polyelectrolyte complexes (PECs) based on an anionic polyelectrolyte (sodium salt of poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS-Na)) and a cationic surfactant ((11-acryloyloxy) undecyl)-trimethylammonium bromide (AUTAB), as well as on PAUTAB cationic comb-like polyelectrolyte and AMPS-Na monomer. IPEC consisting of PAMPS and PAUTAB was obtained by two ways. The first one is polymerization of surface active monomers AUTAB in the presence of PAMPS, and the second one is polymerization of AMPS monomers in the presence of PAUTAB. Molecular hydrodynamics methods were used to determine the molecular properties of initial components, polyelectrolyte complexes (PECs), and IPECs. Analysis of the dependence between translational friction coefficient of macromolecules and their molecular masses (which takes into account excluded-volume effects) allow