Speaker: Tom Witelski, Duke University
Date: November 17, 2016
Title: Multiscale dynamics of dewetting fluid films
Abstract: Instabilities of thin liquid films spreading on solid surfaces are of great concern for many applications involving coating flows. Generally called dewetting instabilities, several stages of dynamics yield rupture, growth of dry spots, and ultimately break-up of the film into sets of droplets. These instabilities can be captured by a lubrication model consisting of a fourth-order nonlinear parabolic PDE for the film height. The long-time behavior can be reduced to a finite-dimensional system for the dynamics of the remaining droplets as interacting quasi-steady localized structures. The final stage, coarsening, is the successive re-arrangement and merging of smaller drops into fewer larger drops. Mean field models can be constructed to describe the evolution of the number of droplets and the distribution of drop sizes yielding macro-scale system properties from the underlying small-scale nonlinear dynamics.