Characterization of polyelectrolyte complexes based on maleic anhydride alternating copolymers by static and dynamic light scattering

The influence of the hydrophobicity of oppositely charged polyelectrolytes based on maleic anhydride alternating copolymers on the complex formation has been investigated by means of DLS and SLS. The change of hydrophobicity of the stock polyions was provided by variation of the comonomer (ethylene, isobutylene and styrene) in the polymer backbone. The particle size and the polydispersity at certain mixing ratios increase with increasing hydrophobicity of the used polyelectrolytes. Below the isoelectric point (1:1 interaction stoichiometry) an increase in the mixing ratio n(-)/n(+) leads to an increasing molar mass and density of the PECs within separate series while the polydispersity decreasing. The radius of gyration and the hydrodynamic radius are less affected by the mixing ratio in this range. Above the isoelectric point, size and molar mass of the PECs increase strongly and depend on the amount and stabilizing efficiency of the added stabilizing efficiency of the added stabilizing poly-electrocyte. All studies PECs are found to be of spherical shape with different internal structure depending on the used polymers and the mixing ratio.