Novel protic ionic liquid-surfactant: Unraveling enhanced micellar interfaces in biocompatible solvents

Abstract

The synthesis and characterization of a novel surfactant derived from AOT, 1-methylimidazolium 1,4-bis-2- ethylhexylsulfosuccinate (imim-AOT), were conducted, revealing its unique ionic liquid properties. Imim-AOT forms reverse micelles (RMs) in biocompatible solvents methyl laurate (ML) and isopropyl myristate (IPM) without the need for a cosurfactant, and its performance was compared with that of the traditional surfactant Na- AOT. 1 Dynamic light scattering studies demonstrated the ability of imim-AOT to solubilize water, forming non- interacting spherical systems. Fourier-transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance ( H NMR) spectroscopy revealed that replacing Na + + with imim + alters the micellar interface properties. Imim-AOT systems showed weaker water-AOT interactions compared to Na-AOT RMs, attributed to the strong imim-water interactions through the NH group of the imidazolium cation. Importantly, no significant differences were observed between micellar systems in IPM and ML, indicating that surfactant conformation dictates interfacial properties rather than the external solvent type. These findings highlight the potential of imim-AOT in nanoreactor applications and underscore its suitability for environmentally benign micellar systems with potential applications in nanomedicine. In summary, our research provides interesting insights into the behavior of protic ionic liquid-surfactant in forming reverse micelles, offering a compelling comparison with traditional surfactants. Our findings demonstrate that the protic ionic liquid-surfactant not only efficiently forms reverse micelles but also exhibits good performance in terms of stability and solubilization capabilities.