Thermal noise influences fluid flow in thin films during spinodal dewetting

TL;DR

This paper demonstrates that thermal noise significantly affects fluid flow and pattern coarsening in thin films during spinodal dewetting, requiring stochastic modeling for accurate predictions.

Contribution

It introduces a stochastic extension to the Navier-Stokes equation to account for thermal fluctuations in thin film dewetting.

Findings

Thermal noise alters the spectrum of capillary waves from exponential to power law decay.

Thermal fluctuations induce coarsening of unstable perturbations over time.

Experimental results align with the stochastic model, highlighting the importance of thermal noise.

Abstract

Experiments on dewetting thin polymer films confirm the theoretical prediction that thermal noise can strongly influence characteristic time-scales of fluid flow and cause coarsening of typical length scales. Comparing the experiments with deterministic simulations, we show that the Navier-Stokes equation has to be extended by a conserved bulk noise term to accomplish the observed spectrum of capillary waves. Due to thermal fluctuations the spectrum changes from an exponential to a power law decay for large wavevectors. Also the time evolution of the typical wavevector of unstable perturbations exhibits noise induced coarsening that is absent in deterministic hydrodynamic flow.