Rogue Nanowaves Driven by Thermal Fluctuations: A New Mechanism for Thin Film Rupture

Liquid films routinely coat solids, forming a protective layer on the eye or a pool of spilt coffee on a table. The most important practical question is whether these films can spontaneously rupture to create a dry spot. Conventionally, rupture is assumed to be driven purely by attractive intermolecular forces between the solid and the liquid, a linear instability, but experiments discovered regimes in which thermal (Brownian) motion is instead responsible, especially for ultra-thin films.

In this talk, a theoretical framework will be developed for the experimentally observed thermal regime, in which fluctuation-induced nanowaves rupture linearly stable films. Molecular simulations identify these regimes and are accurately reproduced by stochastic simulations based on fluctuating hydrodynamics. It is then shown how rare-event theory can be applied to, and developed for, this field for the first time to provide exceptional computational efficiency and accuracy that allows us to extend calculations deep within thermal regime. Furthermore, analysis of the rare-event theory reveals a novel picture of how and when `rogue nanowaves’ are able to provide a route to film rupture. Finally, future applications of the new theoretical framework and experimental verification will be discussed.