Size Effects and Extraordinary Stability of Ultrathin Vapor Deposited Glassy Films of Toluene

作者：Leon Gutierrez E; Garcia G; Lopeandia A F; Clavaguera Mora M T; Rodriguez Viejo J^*

来源：Journal of Physical Chemistry Letters, 2010, 1(1): 341-345.

DOI：10.1021/jz900178u

We report the first experimental evidence of size effects in the glass transition of thin films of an organic molecule grown from the vapor phase. In as-deposited films grown at 90 K (0.80T(g)), both the fictive temperature, T(1), and the Onset of the glass transition, T(on), decrease with thickness. The thinnestlayers (similar to 4 nm) exhibit the highest thermodynamic and lowest kinetic stability. Films refrozen at 2000 K/s after being heated to the liquid state during a previous scan demonstrate no size effects. The width of the glass transition for both as-deposited and refrozen films is independent of the film thickness down to 4 nm. Our heat capacity data suggest that ultrathin vapor-deposited glasses transform into liquid by a faster dynamic influenced by the outer film surface.

• 出版日期2010-1