Abstract
Migration of very thin (Ds increases as the film thickness decreases down to 1 nm, however, below 1 nm, Ds becomes independent of polymer film thickness. The functional dependence of Ds with molecular weight M is described, over the limited range of M in the unentangled regime, by M−1.7 The activation energy for polymer segment hopping is about 41 kJ/mol, which is similar to values obtained from bulk self‐diffusion of other polymers.