Effect of mild nanoscopic confinement on the dynamics of ionic liquids.

Ionic liquids are molten salts without additional solvent and are discussed as innovative solvents and electrolytes in chemical processing and electrochemistry. A thorough microscopic understanding of the structure and ionic transport processes is essential for tailored applications. Here, we study the influence of ``mild'' nanoscopic confinement on the structure and diffusion properties of an ionic liquid, 1-Ethyl-3-methylimidazolium acetate, with scattering techniques. The structure is analyzed with x-ray diffraction, while neutron backscattering spectroscopy is employed for the study of the diffusion processes in these systems. Interpreting the diffusion processes in terms of a jump-diffusion model allowed to deduce confinement effects on the jump length and residence time, both increased at elevated temperatures in confinement. The applied ``mild'' confinement, which leaves room for 10-25 times the domain spacing, allows to observe in much detail how the onset of domain distortion decelerates the dynamics.