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arXiv · 1612.06684

Imbibition triggered by capillary condensation in nanopores

Olivier Vincent·Bastien Marguet·Abraham Stroock
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Abstract

We study the spatio-temporal dynamics of water uptake by capillary condensation from unsaturated vapor in mesoporous silicon layers (pore radius $r_\mathrm{p} \simeq 2$ nm), taking advantage of the local changes in optical reflectance as a function of water saturation. Our experiments elucidate two qualitatively different regimes as a function of the imposed external vapor pressure: for low saturations, equilibration occurs via a diffusion-like process; for high saturations, an imbibition-like wetting front results in fast equilibration towards a fully saturated sample. We show that the imbibition dynamics can be described by a modified Lucas-Washburn equation that takes into account the liquid stresses implied by Kelvin equation.

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Olivier Vincent, Bastien Marguet, Abraham Stroock. 2016-12-20. Imbibition triggered by capillary condensation in nanopores. https://arxiv.org/abs/1612.06684

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