Berlin 2024 – scientific programme

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BP: Fachverband Biologische Physik

BP 4: Computational Biophysics I

BP 4.8: Talk

Monday, March 18, 2024, 17:00–17:15, H 0112

Tensile strength of water with organic impurities — •Marin Šako and Matej Kanduč — Jožef Stefan Institute, Ljubljana, Slovenia

The stability of water is a long-standing problem in physics, studied since the 17th century and continuing to be a subject of investigation today. There is a notable discrepancy between experimental findings and theoretical predictions, as well as inconsistency in measurements across different experiments. While theory predicts that water should be remarkably stable against cavitation, experiments show quite the opposite. In this talk, I will present our work on the conditions that lead to catastrophic cavitation events in decane and water. Additionally, I will discuss how the tensile strength of water is influenced by hydrocarbon impurities, such as oil droplets. We use a framework that combines classical nucleation theory with molecular dynamics simulations. We find that while pure bulk water is exceptionally stable against cavitation, the presence of even tiniest amounts of decane is enough to destabilize water and reduce its tensile strength to experimentally measured lower values. Using our numerical analysis, we find that a decane droplet of a radius of around 1 nm in a macroscopic volume of water is enough to destabilize the system. This is the reason why even in ultra-pure water, the measured tensile strength is significantly lower compared to theoretical predictions. We also find that the curvature correction of surface tension is important to take into account when studying cavitation, nanodroplets, or nanobubbles.

Keywords: cavitation; tensile strength; water; classical nucleation theory; molecular dynamics