Curvature driven flow of thin polymer films and diffusivity measurements

We study the leveling process of nanoindentation-induced defects on polystyrene (PS) films (h = 100-150 nm) spin cast on silicon (Si) surfaces. Leveling occurs upon annealing above the glass transition temperature (T _g) of bulk PS, resulting in a flat polymer surface. The dynamics of the process is recorded with an AFM for PS molecular weights lower and comparable to the critical entanglement point. Diffusivity values measured from the recorded curvature driven flow are found to be in a very good agreement with corresponding self-diffusivity values of bulk PS.