Prediction of Polyelectrolyte Complex Stoichiometry for Highly Hydrophilic Polyelectrolytes

This is the authors' abstract. We don't add key points for this paper.

The interaction between two hydrophilic polyelectrolytes of opposite charges was investigated using poly( l -lysine) (PLL) as the polycation and a library of copolymers of acrylamide and 2-acrylamido-2-methyl-1-propanesulfonate (P(AM- co -AMPS)) with various chemical charge densities as polyanions. The formation of polyelectrolyte complexes (PECs) was comparatively studied by varying different parameters, such as the mixing order, the P(AM- co -AMPS) chemical charge density and the initial polycation to polyanion molar ratio. PECs were then characterized in terms of charge stoichiometry and of stability toward ionic strength. The results showed a strong dependency of precipitated PEC stoichiometry on the P(AM- co -AMPS) chemical charge density and the initial polycation to polyanion molar ratio. In contrast, PEC stoichiometry was not affected by the mixing order of the two polyelectrolyte partners. A general rule capable of predicting the PEC stoichiometry is proposed.