Laboratoire de Physique des Solides
Many aspects of polymers behavior close to interfaces, or when they are confined in thin films are not well understood. Observations related to structural and dynamic behavior indicate that the properties of the polymer thin films differ from the ones we know for the bulk state. There are still questions concerning the glass transition temperature, Tg, the conformation of the chains and their relaxation, density and diffusion coefficient that are highly debated.
In my talk I will present the effect of film thickness reduction on the dynamic properties of polystyrene and poly(2 vinylpyridine). In the case of polystyrene results from dielectric spectroscopy are going to be compared with data from ac-calorimetry. Sample preparation history and polymer substrate interactions are taken in consideration as well for discussing the resulting changes in the properties of the thin films.