Properties of Fluids Composed of Polyelectrolyte and Double-Chain Anionic Surfactant: Branched Polyethyleneimine and Sodium bis(2-ethylhexyl) Sulfosuccinate

The properties of fluids composed of branched polyethyleneimine (PEI) and sodium bis(2-ethylhexyl)sulfosuccinate (AOT) were investigated by steady-state fluorescence, dynamic light scattering, turbidity, conductivity, and pH measurements. Light scattering studies show that addition of PEI into AOT solution can significantly decrease the aggregate size of AOT, however, the aggregate volume of AOT/PEI complexes slightly changes with the [AOT] or [PEI]. 1H NMR spectroscopy measurements show the line shape and chemical shifts of the protons around the head of AOT severely change with increase of [PEI] or [AOT]. It indicates that the interaction of AOT and PEI mainly occurs around the head of AOT.