title: Capillary condensation in a fractal porous medium.
abstract: Small-angle x-ray and neutron scattering are used to characterize the surface roughness and porosity of a natural rock which are described over three decades in length scales and over nine decades in scattered intensities by a surface fractal dimension D = 2.68+/-0.03. When this porous medium is exposed to a vapor of a contrast-matched water, neutron scattering reveals that surface roughness disappears at small scales, where a Porod behavior typical of smooth interfaces is observed instead. Water-sorption measurements confirm that such interface smoothing is due predominantly to the water condensing in the most strongly curved asperities rather than covering the surface with a wetting film of uniform thickness.
authors.affiliation: Institut Français du Pétrole, 92842 Rueil-Malmaison Cedex, France.
authors.forename: D
authors.initials: D
authors.lastname: Broseta
authors.forename: L
authors.initials: L
authors.lastname: Barré
authors.forename: O
authors.initials: O
authors.lastname: Vizika
authors.forename: N
authors.initials: N
authors.lastname: Shahidzadeh
authors.forename: J P
authors.initials: JP
authors.lastname: Guilbaud
authors.forename: S
authors.initials: S
authors.lastname: Lyonnard