Accueil du site Séminaires Soutenance de thèse :

Soutenance de thèse :

Mardi 18 juin 2019 à 14h00,
Salle des séminaires, bâtiment A - CNRS
25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex 9

Orateur : Victor Doebele
"Condensation and evaporation of hexane in porous alumina membranes"

Abstract

I present a study of condensation and evaporation of hexane in porous alumina membranes. This porous material has almost cylindrical pores of nanometric diameter with a narrow pore size distribution. It is therefore an ideal material to probe in a single pore the effects of confinement on the condensation and evaporation mechanisms. I will first discuss my results obtained on membranes with nominally straight pores of 40 nm diameter. Sorption isotherms coupled to a study of the membranes optical behaviour show that the liquid distribution within the pores depends on whether the pores are open at both ends or closed at one end. Comparison of the measurements to numerical simulations implies that the pores are not perfectly cylindrical but funnel shaped and corrugated at the nanometer scale. Second, I will present a study of evaporation in membranes with inkbottle shaped pores. These membranes undergo a systematic and sudden emptying at 33%Psat, as measured by the optic and volumetric signals. I will show that this process corresponds to homogeneous cavitation. This is the first direct observation of such a mechanism in porous membranes. I will finally discuss the prospects raised by these results.

Keywords : Condensation and evaporation, Confinement, Porous medium, Porous alumina membranes, Isotherm measurements, Cellular automaton, Light diffusion, Cavitation

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