Why are choline arginate / choline lysinate mixtures more effective for the pre-treatment of biomass than the pure liquids?

We have recently discovered that certain mixtures of the ionic liquids (ILs) cholinium argininate (Ch[Arg]) and cholinium lysinate (Ch[Lys]) are ~ 20% more efficient for the pre-treatment and dissolution of coal than either pure IL (unpublished). However, the mechanism underpinning this improved performance is unclear, and might be due to synergistic interactions between the anions, changes in the liquid nanostructure, or better capacity to dissolve different coal residues. To resolve this mechanism, we will use SANDALS to investigate Ch[Arg]/Ch[Lys] mixtures at 4 ratios, building off our recent work with both pure ILs (articles in preparation). Understanding why mixtures of Ch[Arg]/Ch[Lys] are high performing will enable rational design of new biomass solvents.