One of my major scientific achievements involves reinterpreting the bulk association of oppositely charged polyelectrolytes and ionic surfactants in an aqueous medium. It has been proven that transparent mixtures formed within a given composition range are charge-stabilized colloidal dispersions of homopolyelectrolyte/surfactant nanoparticles, rather than thermodynamically stable one-phase systems, as previously claimed in the literature. Based on this concept, new methods of preparing stable dispersions of polyelectrolyte/surfactant nanoparticles with controllable properties have been developed. Additionally, it has been demonstrated that the local dilution of these systems significantly impacts their properties, which is directly relevant to home and personal applications. Another significant achievement involves the fabrication of directed interfacial assemblies of oppositely charged components. It has also been established that interactions between oppositely charged polyelectrolytes and surfactants can be confined within an oil/water interface. This can create interfacial films with adjustable permeability, as well as structured, reconfigurable liquids where the shape of one of the liquid phases is locked. Additionally, interfacial complexation of oppositely charged nanoparticles and polyelectrolytes has been shown to stabilize nonequilibrium emulsion structures in aqueous two-phase systems.