la0635294_si_003.pdf (52.66 kB)
Effect of Mixing on the Formation of Complexes of Hyperbranched Cationic Polyelectrolytes and Anionic Surfactants
journal contribution
posted on 2007-04-10, 00:00 authored by Amália Mezei, Róbert Mészáros, Imre Varga, Tibor GilányiThe 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.