2016 年 58 巻 1 号 p. 18-23
We review our neutron scattering studies on hierarchical structure and dynamics of imidazolium-based ionic liquids. In the diffraction patters, a peak reflecting the nanoscale segregation of polar and nonpolar domains appeared at around Q=0.3 Å-1, while a peak due to the ionic correlation at Q=0.8~1.0 Å-1 depending on the anion size. The relaxation of nanostructure, ionic diffusion, imidazolium relaxation and alkyl reorientation were separately observed by means of quasielastic neutron scattering techniques. We have also investigated anion and cation effects on the above motions and revealed that the hierarchical dynamics of the ionic liquids is mainly governed by the coulombic interaction between the polar part of cations and anions.