Temperature-gradient–induced instability in polymer films

Abstract

We report the experimental observation and a theoretical model for a thin-film<br/>instability caused by a temperature gradient. A polymer-air double layer sandwiched between<br/>two plates set to different temperatures shows an instability leading to polymer columns or<br/>stripes spanning the two plates. The characteristic wavelength of these patterns scales inversely<br/>with the initial heat flux through the double layer. Theoretically, we describe the heat flow in<br/>terms of the diffusion of heat through the bilayer, causing an interfacial radiation pressure that<br/>destabilizes the film.