J Chem Phys. 2013 Sep 21;139(11):114704. doi: 10.1063/1.4821128.

Influence of confinement on thermodiffusion.

The Journal of chemical physics

Rachid Hannaoui, Guillaume Galliero, Hai Hoang, Christian Boned

PMID: 24070302 DOI: 10.1063/1.4821128

Abstract

This work focuses on a possible influence of a nanoporous medium on the thermodiffusion of a fluid "isotopic" mixture. To do so, we performed molecular dynamics simulations of confined Lennard-Jones binary equimolar mixtures using grand-canonical like and non-equilibrium approaches in sub- and super-critical conditions. The study was conducted in atomistic slit pore of three adsorbent natures for various widths (from 5 to 35 times the size of a molecule). The simulation results indicate that for all thermodynamic conditions and whatever the pore characteristics, the confinement has a negligible effect on the thermal diffusion factor/Soret coefficient. However, when considered separately, the mass diffusion and thermodiffusion coefficients have been found to be largely influenced by the pore characteristics. These two coefficients decrease noticeably when adsorption is stronger and pore width smaller, a behavior that is consistent with a simple hydrodynamic explanation.

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• Journal Article