Neutron diffraction will be used to investigate and compare the structure of binary mixtures of ionic liquids above and below the critical micelle concentration. Mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate with 1-decyl-3-methyl-imidazolium bromide will be examined as these systems have critical micelle concentrations of ~0.4 M allowing sufficient contrast to be made between the hydrogen and deuterium exchanged samples. This isotopic substitution on both the solvent ([C4mim][BF4]) and the solute (the [C10mim]Br) will enable the specific interactions within the system to be probed and and facilitate the analysis of the data obtained. The deuteriated ionic liquids will be synthesised using methods developed at QUB.