The desorption of polymer chains through an overlayer of strongly adsorbed chains was studied to determine the influence of topological constraints on the polymer desorption process. The desorption time of linear chains fits a power law, ${\mathit{M}}^{\mathit{a}}$, where M is a molecular weight and a=2.3±0.2. A comparison of linear and star-branched chains shows that desorption of star-branched chains was greatly suppressed. These findings are reminiscent of entanglement effects in bulk systems. They suggest a unifying perspective from which to analyze polymer mobility at surfaces.

• Received 4 March 1993

DOI:https://doi.org/10.1103/PhysRevLett.70.3267