The gemini surfactants, O,O’-bis(sodium 2-dodecyl-carboxylate)-p-dibenzenediol and O,O’-bis(sodium 2-decylcarboxylate)-p-dibenzenediol (denoted as C12ϕ2C12 and C10ϕ2C10, respectively), were previously found to form network-like aggregates in very dilute solution. In the present work, the effect of alkyltrimethylammonium bromides, CnNBr, on the network-like aggregates formed by C12ϕ2C12 and C10ϕ2C10 was studied using dynamic light scattering, fluorescence probing, steady-state or frequency sweep rheology, and freeze-fractured TEM measurements. These network-like aggregates were easily transformed into core-shell micelles as CnNBr was added, including spherical micelles and even thread-like micelles, upon increased concentration of CnNBr. On further increasing CnNBr concentration, vesicles were formed. The phase diagrams of aggregate transition were plotted. All of these were attributed to the improvement of added CnNBr on the effective molecule geometry under the base of original columnar-like molecules of C12ϕ2C12/C10ϕ2C10.
