Growing Negative Pressure in Dissolved Solutes: Raman Monitoring of Solvent-Pulling Effect

Lionel Mercury (1, 2) , Kirill Shmulovich (3) , Isabelle Bergonzi (1, 2) , Aurélien Canizarès (4) , Patrick Simon (4)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 Milieux Poreux - UMR7327
3 Institute of Experimental Mineralogy
4 CEMHTI - Conditions Extrêmes et Matériaux : Haute Température et Irradiation

Negative pressure in liquids is both an experimental fact and a usually-neglected state of condensed matter. Using synthetic fluid inclusions, namely closed vacuoles fabricated inside one solid host by hydrothermal processes, a Raman study was performed to examine how a superheated solvent (under negative pressure) interacts with its dissolved solutes. As a result, this contribution not only illustrates this well-known tensile state, but also displays evidence that a stretched solvent is able to pull on its dissolved solutes and put them also under a stretched state. The dielectric continuum hypothesis may lead to expect a stretching effect in solutes similar to the solvent’s, but our measurements evidence a damping mechanical effect (growing with tension), most probably related to solvation shells. One practical consequence is that the (experimentally known) super-solvent properties of superheated solutions are certainly related to the change of the chemical potential of solutes which results from the damping effect. This change can determine as well a change in the thermodynamic driving force of the superheated solution towards bubble nucleation. A more complex than usual picture of the aqueous solution physical chemistry emerges from this study.

Domaines: Planète et Univers [physics]

Lionel Mercury, Kirill Shmulovich, Isabelle Bergonzi, Aurélien Canizarès, Patrick Simon. Growing Negative Pressure in Dissolved Solutes: Raman Monitoring of Solvent-Pulling Effect. Journal of Physical Chemistry C, 2016, 120, pp.7697-7704. ⟨10.1021/acs.jpcc.6b01700⟩. ⟨insu-01293221⟩