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

TitleSize Effects and Extraordinary Stability of Ultrathin Vapor Deposited Glassy Films of Toluene
Publication TypeJournal Article
Year of Publication2010
AuthorsLeón-Gutierrez, E, Garcia, G, Lopeandia, AF, Clavaguera-Mora, MT, Rodríguez-Viejo, J
JournalThe Journal of Physical Chemistry Letters
Volume1
Start Page341
Issue1
Keywordsglass transition, molecular liquid, nanocalorimetry, size effects, ultrathin films, vapor deposition
Abstract

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 (0.80Tg), both the fictive temperature, Tf, and the onset of the glass transition, Ton, decrease with thickness. The thinnest layers (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.

URLhttp://dx.doi.org/10.1021/jz900178u
DOI10.1021/jz900178u
Short TitleThe Journal of Physical Chemistry Letters (2010) 1, 341-345
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