Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 49: Poster: Nanostructures on Surfaces I
O 49.18: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster A
Temperature-dependent stabilization of silver nanoparticles in BMIM PF6 — •Stefanie Roese, Alexander Kononov, Florian Lippert, and Heinz Hövel — Technische Universität Dortmund, Dortmund, Germany
The storage of nanoparticles(NPs) is one of the most challenging tasks. It is indispensable to prevent the NPs from aggregation to larger agglomerates after production. Many groups report that the NPs are electrosterically stabilized without additional agents by ionic liquids(ILs). A detailed review is given by Dupont and Scholten[1]. In addition, due to their low vapour pressure, ILs are ideally suited for vacuum applications. We investigated the temperature-dependent aggregation of preformed 2 nm silver NPs, which were produced by supersonic nozzle expansion and were deposited in a BMIM PF6 IL[2]. With the help of the UV/VIS spectroscopy measurements and the analysis of the theoretically calculated spectra based on the Generalized Mie Theory for various shapes of aggregates, we were able to explain the stability of the samples with the temperature dependence of the viscosity of BMIM PF6[3]. The same approach was also applied to samples produced by sputtering, to investigate the aggregation process. In this case the size distribution of the NPs is not fixed, as the formation of NPs by sputtering is likely to occur on the surface or in the first layer of the IL during and after the sputter deposition. [1] J. Dupont, J. D. Scholten, Chem. Soc. Rev. 39, 1780, (2010). [2] D. C. Engemann, S. Roese, H. Hövel, J. Phys. Chem. 120, 6239, (2016). [3] S. Roese, A. Kononov, J. Timoshenko, A. I. Frenkel, H. Hövel, submitted (2017).