UMR 5672

logo de l'ENS de Lyon
logo du CNRS logo UCBL
You are here: Home / Seminars / Experimental physics and modelling / Nanoscale effects in porous media dynamics : capillary nanoflows, capillary condensation, imbibition and cavitation

Nanoscale effects in porous media dynamics : capillary nanoflows, capillary condensation, imbibition and cavitation

Olivier Vincent (Institut Lumière Matière, Université Lyon 1)
When Oct 02, 2018
from 10:45 AM to 12:00 PM
Where room 115
Attendees Olivier Vincent
Add event to calendar vCal
iCal

Many porous media contain fluids confined at the nanoscale, including a variety of natural (rocks, plant vessels) and industrial (concrete, filters) materials. In this presentation, I will discuss the dynamics of a few specific phenomena that occur in nanopores.

First, I will show that the massive capillary stresses associated with the large curvatures of liquid-vapor interfaces in nanopores can be used to generate significant controlled flows through the porous matrix, a strategy similar to that used by trees to move the water from their roots to their leaves. Analysis of these flows allowed us to probe the dynamic response of nano-confined liquids.

Second, confinement may induce large deviations to the liquid-vapor phase transition, and I will discuss the dynamics of capillary condensation, where vapor spontaneously condenses as a liquid in the nanopores even when far from saturation (~50% relative humidity), and of the subsequent imbibition process.

Last, drying of a material containing nanopores can bring the liquid to strongly metastable states (negative pressure, or tension) that relax suddenly through the nucleation of vapor bubbles (cavitation). I will show that the coupling between nucleation kinetics and transient pressure relaxations results in self-organized periodic bursts of cavitation that are tunable with the geometry of the porous matrix.