Electrostatic Long-Range Interactions in Macromolecules of Flexible-Chain Linear Polyelectrolytes with Low Charge Density in Aqueous Solutions of Different Ionic Strength

Resumo

Molecular hydrodynamics methods (translational diffusion, velocity sedimentation, viscometry) have been used to study copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride with an average content of charged groups (4.4 ± 0.2) mol % in aqueous 0.2 M NaCl solution. Kuhn–Mark–Houwink–Sakurada scaling relationships have been obtained. Viscous flow has been studied in the widest possible range of ionic strengths of aqueous solutions, from salt-free to 6 M NaCl. The data have been compared with those previously obtained for neutral poly-N-methyl-N-vinylacetamide. It has been shown experimentally for the first time that the character of the dependence of the intrinsic viscosity on the molecular mass of a copolymer of such a composition in solutions of minimal ionic strength is typical of the chains exhibiting intrachain volume effects, i.e. electrostatic long-range interactions.