Dynamic Heterogeneity of Polymer Thin Film as Revealed by Neutron Scattering

Abstract

Recently it is well known that the physical properties of polymer thin film are quite different from those of bulk state. Among them glass transition temperature (T_g) of polymer thin film is most extensively studied because T_g is directly related to the thermal stability of polymer thin film in itself, however the detailed mechanism of T_g in thin film is still lacking. In order to overcome such a situation we tried to study the dynamics of polymer thin film by neutron scattering. We found that the low mobility interfacial layer was related to the decrease of mobility with decreasing film thickness by the inelastic neutron scattering studies. From the neutron reflectivity measurements we observed the distribution of T_g in thin film. The dynamic heterogeneity is the essential idea to understand the singular physical properties of polymer thin film.