Light scattering reveals the influence of temperature on collective effects during evaporation and condensation in a disordered porous material

Fabien Bonnet (1) , Mathieu Melich (1) , Laurent Puech (1) , Pierre-Etienne Wolf (1)

1 NEEL - HELFA - Hélium : du fondamental aux applications

We combine high resolution isotherms measurements and light scattering technics to study over a broad temperature range collective effects during the condensation and evaporation of helium from Vycor, a prototypic disordered porous material. For evaporation, our results provide the first direct evidence for a crossover from a percolation collective mechanism at low temperature to a local cavitation mechanism at high temperature. No long range collective effects are detected during condensation. We compare these results to recent theoretical predictions emphasizing the specific role of disorder, and discuss their relevance for determining pores sizes distributions in disordered porous materials.

Mots clés: Liquid Vapor transition; confinement; porous materials; disorder; percolation; cavitation; light scattering

Domaines: Mécanique statistique [cond-mat.stat-mech]; Matière Molle [cond-mat.soft]

Fabien Bonnet, Mathieu Melich, Laurent Puech, Pierre-Etienne Wolf. Light scattering reveals the influence of temperature on collective effects during evaporation and condensation in a disordered porous material. EPL - Europhysics Letters, 2013, 101, pp.16010. ⟨10.1209/0295-5075/101/16010⟩. ⟨hal-00722777⟩