Liquid Ice and Solid Water
Par Wilbert J. Smit, ESPCI Paris, PSL Research University
Mardi 16 juillet, 14h00, Salle des séminaires (215), 2ème étage, Bâtiment A4N
In this seminar, I will discuss two solid-liquid transitions in absence of a phase change. First, I will show how non-linear optical techniques can be used to study the surface structure of ice. By combining a mid-infrared with a near-visible laser beam at a surface, a vibrational spectrum of molecules can be measured with extremely high surface specificity. The vibrational spectrum of the surface of ice is found to strongly resemble that of liquid water at temperatures above –30 °C, which implies the presence of a layer of liquid water at the ice surface (in thermal equilibrium!). This liquid-water layer is directly linked to the slipperiness of ice. In the second part, I will focus on the spreading of yield-stress fluids (gels, creams, pastes, etc.). I will show how the solid-liquid transition in the rheology of these gels influences the film thickness in coating applications.