Thermodynamic properties of interfacial water from its infrared signatures

Isabelle Bergonzi (1) , Lionel Mercury (1) , Frédéric Jamme (2, 3)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 SSOLEIL - Synchrotron SOLEIL
3 CEPIA - Département Caractérisation et Elaboration des Produits Issus de l'Agriculture

Water liquid trapped in quartz micro-cavities is probed by infrared micro-spectroscopy to explore the influence of the solid/liquid and liquid/air interfaces on water thermodynamics. The sample is infraredly mapped with a 3x3 µm micro-beam allowed by the brilliance of synchrotron radiation source (SOLEIL, SMIS beamline) at 2.5 µm xy interval. It appears that the intramolecular OH-stretching band is changing as a function of its proximity to the interfaces. To refine these variations, the band is decomposed into Gaussian components, evidencing that water is interface-printed even at micrometric distance to the wall and/or to the bubble with the closest layer to the interface marked by a dangling-OH effect. Then, these vibrational changes are converted into Gibbs free energy, which range from 35 J.mol-1 4.5 µm away from the interface, to 1 kJ.mol-1 at about 1 µm.

Domains: Continental interfaces, environment; Global Changes

Isabelle Bergonzi, Lionel Mercury, Frédéric Jamme. Thermodynamic properties of interfacial water from its infrared signatures. 16th International Conference on the Properties of Water and Steam, Sep 2013, Londres, United Kingdom. 8 p. ⟨insu-00877516⟩