Study of the glass transition temperature of polymer surface by coarse-grained molecular dynamics simulation

The glass transition temperature at the surface of polymer film is studied by the coarse-grained molecular dynamics simulation. By the analysis of the segmental motion, the glass transition temperatures at the surface region and that in the bulk region are determined separately. The glass transition at the surface region is found to be lower than that in the bulk region. The molecular weight dependence of the glass transition temperature obtained by the simulation agrees well with that obtained by the scanning force microscopic measurements.