|Mon April 24th 2017 |
16:00 – 17:00
|Seminar||Buckling Fluids? A Marangoni-driven Instability in Thin Liquid Films|
Details:Thin fluid film dynamics has been a trove of nontrivial physics with numerous applications. One particularly popular example is thin film dynamics on a rotating substrate. The competition between centrifugal and viscous forces that sets the spreading and thinning dynamics has been of interest for spin coating since the 1950ies. We show with both experiments and numerical modeling that this spreading dynamics can be arrested by adding a static surface tension gradient. This stopping behavior is of finite duration, after which the fluid film "buckles" into a new equilibrium through an abrupt front spreading mechanism. The surface tension gradient force thus seems to produce a temporal mechanical instability. The time dependent dynamics of this process is robust and provides rich scaling behavior with non-trivial scaling exponents.