MasterNanosciences, nanotechnologies

If plants do not have a heart to pump water from the soil, they have the ability to strongly decrease their internal water pressure in the leaves. There, evaporation results in very reduced pressures, down to -190 bars during dry weather! However, under those negative pressures, water can produce cavitation with the sudden nucleation of bubbles. The growth of those bubbles induces a gaseous embolism, progressively filling the hydraulic networks with air. This stops the water circulation and eventually leads to the death of trees. It is not really understood how a plant can recover after such an event, some studies calling for a "miracle", and other some studies suggesting its impossibility and the need for the growth of new tissue.
The main objective of the internship is to understand the physics of the refilling of embolised conduits filled with air, when the humidity level increases. Our approach will be to manufacture biomimetic leaves made of a thin layer of transparent silicone (PDMS), in which we design microfluidic channels (figure) where refilling can be quantified by image analysis (the air embolism appears black). Outcome: We aim at understanding the condition for which a channel can be refilled with water and which is the dynamics of this process.

The student will work in a team with Philippe Marmottant and  Benjamin Dollet, in collaboration with Emmanuel Bossy (acoustic detection). Note that we will collaborate on this topic with a team in Denmark (group of Kaare Jensen, Danish Technical University), specialized in the flows in plants.

Qualifications of the applicant

Soft Nano Program:  M1 Soft Matter and Biophysics - Applied Mechanics -  Phelma Biomedical Engineering