Addressing the Interaction of Ether-Functionalized Pyrrolidinium-Based Surface-Active Ionic Liquid with Anionic Surfactants: A Tensiometric and Computational Simulation Study

The present study addresses the aggregation behavior of an ether-functionalized pyrrolidinium-based surface-active ionic liquid (hereafter abbreviated as SAIL) and its interaction with analogous anionic surfactants with minimal structural difference. The aggregation pattern of cationic SAIL has been investigated in the presence of sodium linoleate and sodium oleate by using surface tension (γ) measurements. Various theoretical models for mixed binary systems have been used to analyze γ data. The information about the variation in surface activity and critical micelle concentration (CMC) driven by the alteration in the composition of the binary mixture has also been evaluated. The contributions of the electrostatic interaction, H-bonding, hydrophobic interaction, and van der Waals interaction in mixed micellization behavior have also been discussed. Various thermodynamic and interfacial parameters for mixed systems at different mole fractions of SAIL have been computed and analyzed. Different optimized parameters obtained from a computational simulation approach have been employed to correlate the molecular orbital energy level of sodium oleate or sodium linoleate and SAIL. Changes in size and architecture of SAIL aggregates have also been estimated using dynamic light scattering (DLS) study. The outcome of the present study offers an additional route to formulate mixed nano aggregates from pyrrolidinium-based SAIL and analogous anionic surfactants.