| The surface of a thin liquid film with nonconstant curvature is unstable, as the Laplace pressure drives a flow mediated by viscosity. We present experiments and theory on a very simple system: a thin stepped polymer film. The evolution of the profiles is shown to be self-similar. The experiments and theory are in excellent agreement which indicates the effectiveness of stepped polymer films to elucidate nanoscale rheological properties such as slip, confinement and disjoining pressure effects. Other geometries such as the leveling of a polymer droplet are explored. We also present the linear thin film equation which is a good approximation to describe small perturbations at the surface of a thin film. We derive the Green’s function of the problem and prove the existence of a universal attractor. The results are extended numerically to the nonlinear thin film equation. |
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