Formation of Multilayer Polyelectrolyte Complexes by Using Block Ionomer Micelles as Nucleating Particles

• Published in: The journal of physical chemistry. B 2004-08, Vol.108 (33), p.12352-12359
• Main Authors: Lysenko, Evgeniy A, Chelushkin, Pavel S, Bronich, Tatiana K, Eisenberg, Adi, Kabanov, Victor A, Kabanov, Alexander V
• Format: Article
• Language: English
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp048777s

This study focuses on the complexes formed between polystyrene-block-poly(N-ethyl-4-vinylpyridinium bromide) (PS-b-PEVP) and poly(sodium methacrylate) (PMANa). These complexes were synthesized as follows. First, PS-b-PEVP is dispersed in water, which results in the formation of the micelles with insoluble PS core and cationic PEVP corona. Second, these micelles are reacted with the linear polyanion, PMANa. This leads to formation of the polyion complex micelles that are likely to have the multilayer structure:  the PS core surrounded by the intermediate insoluble layer of mutually neutralized polyions and the lyophilizing shell of the polyion that is present in excess. The complexes were characterized by UV and fluorescence spectroscopy, sedimentation velocity, viscometry, static and dynamic light scattering, ζ-potential measurements, and transmission electron microscopy. The properties and stability of the complexes in aqueous dispersion depends on the ratio of charged units of the polycation and polyanion chains, Z = [PMANa]/[PEVP]. The shell can be either cationic (PEVP) if the polycation is in excess (Z ≤ 0.3) or anionic (PMANa) if the polyanion is in excess (Z ≥ 1.8). When Z values are intermediate 0.3 < Z < 1.8 the micelles become unstable in dispersion and precipitate. At 0.6 ≤ Z ≤ 1.3 only the insoluble complexes are formed. Overall, reacting the polyelectrolyte micelles with oppositely charged linear polyelectrolytes represents a simple and effective method of modification of polyelectrolyte micelles and synthesis of micellar dispersions of polyelectrolyte complexes.