CRITICAL-DYNAMICS OF A POLYMER-CHAIN IN A GRAFTED MONOLAYER

The dynamic behavior of polymer chains grafted onto a planar inert surface and forming a monolayer is considered. It is found that the molecular weight dependence of the time of large-scale chain relaxation in a monodisperse layer is tau approximately N3, which is in accordance with the molecular dynamics data. This dependence is retained upon the wide-range variation in grafting density and solvent quality. It is shown that anomalous chain relaxation is due to the critical slowing-down near the coil-stretch transition point. Analogy with a macromolecule in an elongational flow is established and analyzed. Polydispersity of chains forming the layer affects dramatically their global relaxation times.