Colloid solution of surfactant monomers and polyelectrolyte: Polymerization and properties of the resulting interpolyelectrolyte complexes

Abstract

In the present work, we suggest a novel method for obtaining interpolyelectrolyte complex (IPEC) by free radical polymerization in water–salt dispersions of polyelectrolyte complexes (PECs) based on an anionic polyelectrolyte (sodium salt of poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS-Na)) and a cationic surfactant ((11-acryloyloxy) undecyl)-trimethylammonium bromide (AUTAB), as well as on PAUTAB cationic comb-like polyelectrolyte and AMPS-Na monomer. IPEC consisting of PAMPS and PAUTAB was obtained by two ways. The first one is polymerization of surface active monomers AUTAB in the presence of PAMPS, and the second one is polymerization of AMPS monomers in the presence of PAUTAB. Molecular hydrodynamics methods were used to determine the molecular properties of initial components, polyelectrolyte complexes (PECs), and IPECs. Analysis of the dependence between translational friction coefficient of macromolecules and their molecular masses (which takes into account excluded-volume effects) allowed us to determine the Kuhn segment length of PAMPS-Na macromolecule (A=6nm). Stable polyelectrolyte complexes, PEC, (PAMPS–AUTAB and PAUTAB–AMPS) were obtained by mixing solutions of components at low concentrations in equimolar ratios; polymerization of their low molecular weight components was carried out for the purpose of preparing IPECs. Comparison between scattered light intensity distributions measured for PEC and IPEC demonstrated that in IPEC solutions, only large aggregates of complex molecules are present, while in PEC solutions, two peaks were observed (those corresponding to diffusion of individual PECs and their aggregates). When concentrations of PEC components exceed 3.4mM, polymerization results in the formation of IPEC precipitate which was studied by small angle X-ray scattering. It was found that the IPEC based on PAMPS-Na forms a film with hexagonal packing, and the PAUTAB-based IPEC forms a lamellar film.