Leveling and dewetting processes of nanoindentation-induced defects on thin polymer films

study the effect of nanoindentation-induced indents on polystyrene (PS) fil ms (thickness = h > 100 nm); spin-cast on silicon substrates. Indents with residual depths of penetration, zn, comparable to the film thicknesses leve led (healed) upon heating above the glass transition temperature (T,) of bu lk PS, resulting in a flat polymer surface. Deep indents which clearly pene trated the films and damaged the substrate dewetted from the silicon surfac e. The healing rate, dz(D)/dt, was measured for several molecular weight PS films and found to scale with the curvature of the hole bottom, H-D, as (d z(D)/dt) HD0.52 +/-0.05. Measurements were performed using atomic force mic roscopy. The healing rate was found to be, in general, higher than the dewe tting rate of the laterally expanded deep indents.