Small-angle x-ray diffraction of Kr in mesoporous silica: Effects of microporosity and surface roughness

Journal Article · Mon Aug 01 04:00:00 EDT 2005 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.72.064122· OSTI ID:20719309

Hofmann, T; Wallacher, D; Huber, P; Birringer, R; Knorr, K; Schreiber, A; Findenegg, G H ^[1]

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1. Technische Physik, Universitaet des Saarlandes, D-66041 Saarbruecken (Germany)

Kr has been adsorbed in SBA-15, a template-grown mesoporous silica substrate. A volumetric adsorption isotherm is presented. The Bragg peaks of the pore array have been measured by small angle x-ray diffraction and analyzed as function of the filling fraction in terms of the electron density contrast, the radial position of the liquid-vapor interface, and film roughness, both for the regime of film growth and capillary condensation. The results are compared with the theory of Saam and Cole. It is shown that the microporosity of the matrix leads to a delay of capillary condensation. The peculiar dependence of the film thickness on the filling fraction points to a high fractal dimension of the pore walls.

• OSTI ID: 20719309
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 6 Vol. 72; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ADSORPTION
ADSORPTION ISOTHERMS
BRAGG CURVE
CAPILLARIES
ELECTRON DENSITY
FILM CONDENSATION
FILMS
FRACTALS
INTERFACES
KRYPTON
LAYERS
POROSITY
POROUS MATERIALS
ROUGHNESS
SILICA
SUBSTRATES
SURFACES
VAPORS
X-RAY DIFFRACTION