Exponentially fast thinning of nanoscale films by turbulent mixing

Films are nanoscopic elements of foams, emulsions, and suspensions that form a paradigm for nanochannel transport that eventually tests the limits of hydrodynamic descriptions. Here, we study the collapse of a freestanding film to its equilibrium. The generation of nanoscale films usually is a slow linear process; using thermal forcing we find unprecedented dynamics with exponentially fast thinning. The complex interplay of thermal convection, interface, and gravitational forces yields optimal turbulent mixing and transport. Domains of collapsed film are generated, elongated, and convected in a beautiful display of chaotic mixing. With a time scale analysis, we identify mixing as the dominant dynamical process responsible for exponential thinning.