Communication: Inflection in the pressure dependent conductivity of the protic ionic liquid C8HIM NTf2

Temperature and pressure dependent broadband dielectric measurements were performed on the proticionic liquid C8HIM NTf2 over a frequency range from 0.1 Hz to 1 MHz. The temperature dependenceof the inverse dc-conductivity exhibits the super-Arrhenius like behavior typical for glass formingmaterials. However, in the pressure dependence both slower and faster than exponential developmentsoccur, resulting in an inflection in the corresponding curves. The experimental data was successfullyfitted with a model incorporating both features. While similar transitions have been observed in thepressure dependent viscosity or structural relaxation times, this is the first time such a behavior isreported in the conductivity.