Ion Dynamics in Ionic Liquids as seen by QENS
Project details
The materials class of ionic liquids has attracted an enormous research interest in the past few years. This huge interest in these liquids is mainly due to the fact that ionic liquids offer very often an attractive alternative to conventional reaction media. In our project we focus on pyridinium-based ionic liquids. The main tool for investigating the dynamics occurring in these liquids is quasi-elastic (QENS) and inelastic neutron scattering (INS). QENS [1] allows for studying localized dynamical processes (rotations, librations, jump-processes etc.), while INS provides information on interionic interactions.
These processes depend on the geometry of the ions and the local environment given by surrounding neighbors. With the help of polarized neutrons [2] we can separate coherent from incoherent scattering contributions and thus collective dynamical processes from single-particle dynamics (see figure). Furthermore we use deuteration techniques to highlight the scattering contribution from specific parts (either the pyridinium ring or the alkyl-chain) of the cation under investigation. Comparing the results of these experiments allows us to understand the contribution of each part of the cation to the overall dynamics [3].
References
References
- [1] J.P.Embs et al., Z.Phys.Chem.2010, 224, 5-32
- [2] J.P.Embs et al., J.Phys.Chem. B 2012, 116, 13265-13271
- [3] J.P.Embs et al., J.Phys.Soc.Jpn. 2013, accepted