Spontaneous formation of vesicles by N-dodecyl-N-methylpyrrolidinium bromide (C12MPB) ionic liquid and sodium dodecyl sulfate (SDS) in aqueous solution

The spontaneous formation of vesicles in an aqueous catanionic mixture, composed of a cationic surface active long-chain ionic liquid N-dodecyl-N-methylpyrrolidinium bromide (C12MPB) and an anionic surfactant sodium dodecyl sulfate (SDS), is investigated. The phase behavior of catanionic system is studied and the phase diagram is mapped through visual observation and electrical conductivity measurement. The vesicles formed in the lamellar phase (Lα) are characterized by transmission electron microscopy (TEM). The macroscopic properties of birefringent Lα phase are investigated by rheological measurements. The hydrophobic and electrostatic interactions are regarded as the main driving forces for spontaneous formation of vesicles.