Abstract:

It may seem surprising that we can lower the pressure in a liquid to negative values, far below the saturated vapor pressure at which a vapor phase should form. In water, such deeply metastable states are possible only when it is exceptionally pure and free of nucleation sites. It is therefore even more striking that plants transport water at negative pressures down to -100 atm without cavitation, even though xylem sap is anything but pure: it contains dissolved ions, sugars, lipids, and other organic molecules. How is this possible?

In this talk, I will show how molecular simulations and theory can explain this surprising behavior. We find that amphiphilic molecules such as lipids can adsorb onto hydrophobic surface crevices – places that would normally trap nanobubbles. Once coated, these surface defects can no longer stabilize bubbles, which allows water to stay intact even under strong tension. This mechanism offers a molecular-level explanation for how trees transport water to heights of over 100 meters without cavitation. More broadly, it illustrates how soft-matter physics and interfacial molecular organization can control the mechanical stability of liquids under extreme conditions.

Bio:

Matej Kanduč is a Senior Research Associate at the Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana, Slovenia. His research combines theoretical physics and molecular simulations to investigate soft-matter and biophysical systems, with a focus on biological membranes, surfactants, wetting phenomena, hydrophobic interactions, foam stability, and cavitation in liquids.

After completing his PhD in Physics at the University of Ljubljana, he held research positions at the Technical University Munich, Free University Berlin, and Helmholtz Center Berlin, supported in part by an Alexander von Humboldt Fellowship. In 2018, he returned to Slovenia and joined the Jožef Stefan Institute, where he leads research on interfacial phenomena and biological liquids. He currently serves as President of the Slovenian Biophysical Society.