Polymer thin films as a route to access low energy glassy states

Resumen del trabajo presentado al APS March Meeting, celebrado en Baltimore, Maryland (USA) del 14 al 18 de marzo de 2016.We investigate the enthalpy recovery in the glassy state of stacked polystyrene films with thickness 30 nm. We first show how the equilibrium dynamics and thermodynamics of such films is mainly bulk-like. When studying enthalpy recovery, we find two mechanisms of equilibration: one showing up below 348 K, that is, the films Tg; and the second active below 308 K. The latter mechanism appear to have low activation energy and, as a result, gives rise to dramatic decrease of the effective temperature Tf within relatively short aging times. This allows to achieve low energy glasses, in particular approaching the Kauzmann temperature (Tk), that is, the temperature at which the entropy of the glass equals that of the crystal. The implications of our results are discussed.Peer reviewe