(123e) Properties of Free Standing Glassy Films

We present a detailed overview of the thermodynamic stability and structural properties of free standing glassy films, investigated using molecular dynamics simulations of a 80-20 binary Lennard-Jones mixture. Energy minimization calculations are also preformed to study the underlying inherent structures. We note that at equilibrium, species separation is evident in the film, and that the interior density and interface thickness are dependent solely on temperature. The atoms at the surface of the film have a higher diffusivity when compared to the interior. The average difference between the equilibrium and inherent structure energies, as a function of the distance from the center of the film, increases towards the surface. This suggests that the surface atoms are able to sample the underlying energy landscape more efficiently. These results are not inconsistent with the recent discovery by Ediger and coworkers of exceptionally stable glasses formed by slow vapor deposition (Swallen et al. Science, 315, 353, 2007)