Enthalpy Recovery in Nanometer to Micrometer Thick Polystyrene Films

摘要: The physical aging of polystyrene (PS) free-standing films has been investigated as a function the thickness, ranging from several micrometers to tens nanometers. In this range thicknesses, unchanged segmental dynamics in comparison bulk was previously reported. This study carried out through differential scanning calorimetry (DSC), by following enthalpy recovery monitor process at different temperatures. temperature marking onset nonequilibrium effects, that is glass transtion temperature, Tgon, also assessed, cooling rates. An acceleration process, and consequently depression found with decreasing already for thicknesses micrometer range. Moreover, effects shown be rate dependent, being more pronounced when PS get thinner. thickness on typical signatures out-of-...