Self-assembly and structure in ionic liquids and their mixtures

In this work self-assembled bulk nanostructure and solvation structures in ionic liquids (ILs) and their solutions are probed. This has been done using neutron diffraction and empirical potential structure refinement (EPSR) simulated fits. Solvate ionic liquids (SILs) have attracted increasing research attention in recent years, with significant attention attracted to understanding their liquid structure. Here, the bulk nanostructures of a prototypical ‘good’ and ‘poor’ SIL are probed. The EPSR fits produced represent the first work to study the bulk liquid of any SIL using simulations refined against experimentally measured diffraction data, revealing a wide variety of different complex structures are present. Additionally, the solvation of representative charged, polar and apolar solutes (chloride, glycerol and octanol respectively) is examined in common protic ILs. In all solutions examined the IL-based solutions are found to be highly structured, with bulk morphologies related to, but distinct from, the native IL nanostructures. Together this work contributes to the growing understanding of how the balance of IL–IL, IL–solute and solute–solute interactions influence IL-based solution structure. Finally, the influence of bulk nanostructure on a macroscopically measured transport property, thermal conductivity, is probed. The thermal conductivities of nine pure protic ILs and two IL-based solutions are measured and analysed using the Bahe-Varela pseudolattice theory, showing that the repeat lengths associated with polar-apolar domain alternation in the bulk liquids limit the efficiency of thermal transport.