Temperature Dependence of Structural Parameters of Thin Films of Polystyrene−Fullerene С₆₀/С₇₀ Nanocomposite According to Neutron Reflectometry Data

The temperature dependences of the structural parameters of thin films of polystyrene–fullerene C₆₀/C₇₀ nanocomposites with a low content of nanoparticles in the vicinity of the glass transition temperature of the polymer matrix were studied by specular neutron reflectometry in the range of 15–150°C. The obtained temperature dependences of film thickness were used to estimate the glass transition temperature of film composites. In the case of films with C₆₀ fullerene, the dependence had a standard form. The glass transition temperature of the composite film was found to decrease compared to the known value for the pure bulk polymer. In the case of films with C₇₀ fullerene, upon transition to high temperatures, a nonmonotonic dependence of the film thickness was observed, which hindered application of the general approach.