Multiscale dynamics of water in metal-oxide nanochannels

Post-doctoral allowance, 18 months, AAP 2017-1

Team : Laboratoire de Physique des Solides

Abstract :

Fluids at the nanoscale present new dynamical and diffusion properties. Highlight may be put, for instance, on the tremendously enhanced water permeability of carbon nanotubes. Understanding water dynamics in nanochannels appears of considerable interest for fundamental science as well as for applications including desalination, nano-filtration and energy harvesting. However, up to now, only a very few experimental investigations are available. We thus propose here to perform such a study.

The subject of the post-doctoral work, to be supervised by Pascale Launois at Laboratoire de Physique des Solides (Orsay) and by Pierre Levitz at laboratoire PHENIX (Paris), is the multiscale dynamics of water in metal-oxide nanochannels. The nanochannels used are hydrophilic and hydrophobic imogolite-like nanotubes. Their internal pores offer one of the rare possibility to probe the confined dynamics of water in well-defined geometries and for different interactions with the interface. Such dynamics should be a multiscale process involving an interplay between vicinal interaction with the pore wall and constrained dynamics inside the restricted geometry of the cylindrical pore. The post-doctoral researcher will mainly deal with dynamical experiments at different time scales, namely Time-of-Flight and neutron spin echo experiments, which will allow him (her) to probe dynamics inside a correlation time window below the ns, and Nuclear Magnetic Resonance (NMR) Dispersion and bi-dimensional T₂-D-T₂ NMR relaxometry, with a special focus on a time window ranging from few ns to 10 ms. The work will lean back against the equipment of the involved teams (Erwan Paineau, Stéphan Rouzière and Pascale Launois, Laboratoire de Physique des Solides, Orsay: X-ray diffractometer and controlled humidity chamber for in-situ X-ray scattering, for the study of the hydration of the samples; Pierre Levitz, Anne-Laure Rollet and Guillaume Meriguet for the Relaxometry platform of laboratoire PHENIX). Neutron experiments will be performed at French or European neutron facilities, in collaboration with Stéphane Rols from Institut Laue Langevin. Our objective is to obtain a consistent set of new data about the multiscale dynamics of water in model nanoporous media (namely, hydrophilic and more hydrophobic nanotubes), and to present a first global picture of the associated phenomena.

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