The surface dynamics of thin molten polystyrene films supported by nanoscale periodic silicon line-space gratings were investigated with X-ray photon correlation spectroscopy. Surface dynamics over these nanostructures exhibit high directional anisotropy above certain length scales, as compared to surface dynamics over flat substrates. A cutoff wavelength in the dynamics perpendicular to the grooves is observed. This marks a transition from standard over-damped capillary wave behavior to suppressed dynamics due to substrate interactions.
Citation: Physical Review Letters
Pub Type: Journals
capillary waves, liquid films, polymers, viscosity, confinement, nanopatterning, X-ray photon correlation spectroscopy