title: Effect of mixing on the formation of complexes of hyperbranched cationic polyelectrolytes and anionic surfactants.
abstract: The effect of different mixing protocols on the charged nature and size distribution of the aqueous complexes of hyperbranched poly(ethylene imine) (PEI) and sodium dodecyl sulfate (SDS) was investigated by electrophoretic mobility and dynamic light scattering measurements at different pH values, polyelectrolyte concentrations, and ionic strengths. It was found that at large excess of the surfactant a colloidal dispersion of individual PEI/SDS nanoparticles forms via an extremely rapid mixing of the components by means of a stop-flow apparatus. However, the application of a less efficient mixing method under the same experimental conditions might result in large clusters of the individual PEI/SDS particles as well as in a more extended precipitation regime compared with the results of stop-flow mixing protocol. The study revealed that the larger the charge density and concentration of the PEI, the more pronounced the effect of mixing becomes. It can be concluded that an efficient way to avoid precipitation in the solutions of oppositely charged polyelectrolytes and surfactants might be provided by extending the range of kinetically stable colloidal dispersion of polyelectrolyte/surfactant nanoparticles via the application of appropriate mixing protocols.
authors.affiliation: Laboratory of Interfaces and Nanosized Systems, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, PázmAny Péter sétány 1/A, Hungary.
authors.forename: Amália
authors.initials: A
authors.lastname: Mezei
authors.forename: Róbert
authors.initials: R
authors.lastname: Mészáros
authors.forename: Imre
authors.initials: I
authors.lastname: Varga
authors.forename: Tibor
authors.initials: T
authors.lastname: Gilányi
mesh_terms: D000838:Anions; D002412:Cations; D002627:Chemistry, Physical / Q000379:methods; D004573:Electrolytes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008027:Light; D053758:Nanoparticles / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry*; D012542:Scattering, Radiation; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000838:Anions; D002412:Cations; D004573:Electrolytes; D007477:Ions; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D011094:Polyethyleneimine