Dresden 2020 – wissenschaftliches Programm
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CPP 19.7: Vortrag
Montag, 16. März 2020, 16:30–16:45, ZEU 222
Ionic liquid cation dynamics in carbon nanoconfinement: A pore size and temperature-dependent neutron spectroscopy study — •Mark Busch1, Tommy Hofmann2, Bernhard Frick3, Jan P. Embs4, Boris Dyatkin5, and Patrick Huber1 — 1Institute of Materials Physics and Technology, Hamburg University of Technology, Hamburg, Germany — 2Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany — 3Institut Laue-Langevin, Grenoble, France — 4Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, Switzerland — 5Dept. of Materials Science and Engineering, Drexel University, Philadelphia, U.S.A.
The temperature-dependent cation dynamics of the room-temperature ionic liquid [BuPy][Tf2N] within the nanoconfinement of carbide-derived carbons with various pore sizes are investigated by quasi-elastic neutron spectroscopy. An overview of the dynamic landscape over a wide temperature range is obtained by employing fixed window scans, where one sample parameter is scanned, while only one specific energy transfer value is observed. These data that provide already a quite comprehensive understanding of the confinement-induced alteration of the molecular mobility in comparison to the bulk are complemented by a more detailed analysis of full energy transfer spectra. Two diffusive processes on different time scales are found. Both are considerably slower than in the bulk and the corresponding self-diffusion coefficients decrease with decreasing nanopore size. In spite of this dynamic slow down, the temperature range of the liquid state upon nanoconfinement is found to be notably extended to much lower temperatures.