X-ray reflectivity theory for determining the density profile of a liquid under nanometre confinement
- Perret, Edith Paul Scherrer Institut, Villigen PSI, Switzerland
- Nygård, Kim Paul Scherrer Institut, Villigen PSI, Switzerland
- Satapathy, Dillip Kumar University of Fribourg
- Balmer, Tobias E. ETH Zurich, Switzerland
- Bunk, Oliver Paul Scherrer Institut, Villigen PSI, Switzerland
- Heuberger, Manfred EMPA, St Gallen, Switzerland
- Veen, J. Friso van der Paul Scherrer Institut, Villigen PSI, Switzerland - ETH Zurich, Switzerland
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2010
Published in:
- Journal of Synchrotron Radiation. - 2010, vol. 17, no. 4, p. 465-472
English
An X-ray reflectivity theory on the determination of the density profile of a molecular liquid under nanometre confinement is presented. The confinement geometry acts like an X-ray interferometer, which consists of two opposing atomically flat single-crystal mica membranes with an intervening thin liquid film of variable thickness. The X-rays reflected from the parallel crystal planes (of known structure) and the layered liquid in between them (of unknown structure) interfere with one another, making X-ray reflectivity highly sensitive to the liquid's density profile along the confinement direction. An expression for the reflected intensity as a function of momentum transfer is given. The total structure factor intensity for the liquid-filled confinement device is derived as a sum of contributions from the inner and outer crystal terminations. The method presented readily distinguishes the confined liquid from the liquid adsorbed on the outer mica surfaces. It is illustrated for the molecular liquid tetrakis(trimethyl)siloxysilane, confined by two mica surfaces at a distance of 8.6 nm.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 20298
- DOI 10.1107/S0909049510014858
- Persistent URL
- https://folia.unifr.ch/unifr/documents/301556
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