Contact line dynamics
How fast can a liquid drop slide over a solid surface? The maximum speed is strongly limited by the dynamics of the contact line that marks the boundary of ‘wet’ and ‘dry’ surface: viscous friction is extremely large near the contact line where molecules quickly slide over each other. Upon approaching the maximum speed, one encounters a wealth of phenomena such as singularities and instabilities. Besides intrinsic interest, these instabilities of the contact line are of great importance for applications that crucially rely on a perfect control over the liquid domain. An example is shown in the context of Immersion Lithography, a technology developed by ASML Netherlands. We combine experimental and theoretical methods to address both fundamental problems and technological issues of contact line dynamics.