(13b) Modulating the Self-Assembly of 1-n-Dodecyl-3-Methylimidazolium Octylsulfate Biamphiphilic Ionic Liquid

One of the reasons ionic liquid solvents have gained major interest in chemical industries as a green alternative is due to their strong ability to solvate both polar and nonpolar species simultaneously along with their non-volatile nature owing to their negligible vapor pressure. Ionic liquid with high amphiphilic character and mesoscale nanosegregated structures are attractive for biocatalytic chemical processes. It has been established that potential candidate for such applications is highly dependent on the morphological heterogeneities of polar-nonpolar domains. It is believed that precise control over such molecular level segregation can be obtained by modulating the competition between the electrostatic interactions of the ionic moieties in ionic liquid and short-range attractive interactions between the nonpolar regions. Previously, we demonstrated that the ionic liquid morphology can be tuned from sponge-like to layer-like with the increase in the cationic alkyl chain with the contributions to nonpolar domain formation from both the ions. In fact, 1-n-dodecyl-3-methylimidazolium [C₁₂mim] octylsulfate [C₈SO₄] portrayed nanoscale structuring (polar–nonpolar–polar) over multiple length scales. In this work, we employ molecular dynamics simulations to investigate change in the morphology of [C₁₂mim] [C₈SO₄] ionic liquid using two approaches: (a) exposing the ionic liquid to vacuum; (b) mixing the ionic liquid with molecular solvents of varying polarity, that includes water (polar) and 1-octanol (amphiphilic). The characterization of structural features will be discussed in terms of structure factors, number densities, order parameters, and instantaneous simulation snapshots.