POLYCATION-POLYANION COMPLEXES IN THE LINEAR DIBLOCK COPOLYMER OF POLY(STYRENE SULFONATE)-POLY(2-VINYLPYRIDINIUM) SALT

From spectrophotometric analysis in aqueous medium, the degree of ionization of poly(2-vinylpyridine) in a linear diblock copolymer of a poly (styrene sulfonate) / poly (2-vinylpyridine) salt was obtained as a ftmction of pH. The spectrophotometric titration curve was compared with the titration curves of a diblock copolymer of polyethylene oxide)/poly(2-vinylpyridine) and of homopoly(2-vinylpyridine). The strong increase of basicity of pyridine groups in the polyampholyte copolymer is explained by invoking a stoichiometric interaction between oppositely charged groups. The formation of an internal polysalt is discussed in relation to conformational changes obtained from viscosity data. © 1979, American Chemical Society. All rights reserved.