Variation in glass transition temperature of polymer nanocomposite films driven by morphological transitions.

We report the variation of glass transition temperature in supported thin films of polymer nanocomposites, consisting of polymer grafted nanoparticles embedded in a homopolymer matrix. We observe a systematic variation of the estimated glass transition temperature T(g), with the volume fraction of added polymer grafted nanoparticles. We have correlated the observed T(g) variation with the underlying morphological transitions of the nanoparticle dispersion in the films. Our data also suggest the possibility of formation of a low-mobility glass or gel-like layer of nanoparticles at the interface, which could play a significant role in determining T(g) of the films provided.