We have investigated the oscillations of the disjoining pressure, corresponding to film stratification, for foam films containing small concentrations of ionic surfactants and carboxymethylcellulose, an anionic polysaccharide. In water, this polyelectrolyte does not form surface complexes with AOT, an anionic surfactant. However, when mixed with cationic surfactants, in this case alkyltrimethylammonium bromides (C(n)TAB), strong polymer-surfactant interactions create an enhanced coadsorption of both components at the air-water interface that strongly depends on surfactant concentration. We have found stratification phenomena whatever the nature of the surfactant. The oscillation period of the disjoining pressure varies with the polymer concentration as C-p(-1/2), and is close to the mesh size defined for semidilute polymer solutions. However, the dynamic properties of the liquid films and their stability are in turn very sensitive to the nature of the surfactant charge, as revealed from the behavior of the stratification kinetics.