Polyelectrolyte-Surfactant Complexes Formed by Poly-[3,5-bis(trimethylammoniummethyl)4-hydroxystyrene iodide]-block-poly(ethylene oxide) and Sodium Dodecyl Sulfate in Aqueous Solutions
Abstract
Formation of polyelectrolyteMINUS SIGN surfactant (PEMINUS SIGN S) complexes of poly[3,5-bis(trimethylammoniummethyl)-4-hydroxystyrene iodide]-block-poly(ethylene oxide) (QNPHOSMINUS SIGN PEO) and sodium dodecyl sulfate (SDS) in aqueous solution was studied by dynamic and electrophoretic light scattering, SAXS, AFM, and fluorometry. SAXS data from the QNPHOSMINUS SIGN PEO/SDS solutions were fitted assuming contributions from free copolymer, PEMINUS SIGN S aggregates described by a mass fractal model, and densely packed surfactant micelles inside the aggregates.
It was found that, unlike other systems of a double hydrophilic block polyelectrolyte and an oppositely charged surfactant, PEMINUS SIGN S aggregates of the QNPHOSMINUS SIGN PEO/SDS system do not form coreMINUS SIGN shell particles and the PEMINUS SIGN S complex precipitates before reaching the charge equivalence between dodecyl sulfate anions and QNPHOS polycationic blocks, most likely because of conformational rigidity of the QNPHOS blocks, which prevents the system from the corresponding rearrangement.