title: Capillary wave dynamics of thin liquid polymer films.
abstract: The dynamics of thin, liquid polybutadiene films on solid substrates at temperatures far above the glass transition temperature T(g) was studied by Resonance Enhanced Dynamic Light Scattering. The capillary wave dynamics is the stronger suppressed by the substrate the thinner the film. We find a molecular weight independent film-thickness below which the dynamics change dramatically--the viscosity increases by orders of magnitude. This change is not related to 3R(g) as postulated in theory and claimed in some experimental findings but rather to a fixed distance from the solid interface. Part of our observations we attribute to a, compared to bulk polymer, less mobile viscoelastic layer adjacent to the substrate, and part to a more mobile layer at the liquid-gas interface. Thus, the overall behavior of the dynamics can be explained by a "three layer" model, the third layer having bulk behavior in between the above two layers.
authors.affiliation: Max Planck Institute for Polymer Research, P.O. Box 3148, 55128 Mainz, Germany.
authors.forename: Fan-Yen
authors.initials: FY
authors.lastname: Lin
authors.affiliation: Max Planck Institute for Polymer Research, P.O. Box 3148, 55128 Mainz, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Steffen