title: Accelerated aging in ultrathin films of a molecular glass former.
abstract: We report the thermodynamic measurement of the enthalpy released during the aging of supported films of a molecular glass former, toluene, at temperatures well below the glass transition temperature. By using microfabricated devices with very short equilibration times (below 1 s), we evidence a remarkable variation of the relaxation rate on decreasing film thickness from 100 nm down to a 7 nm thick film. Our results demonstrate that surface atoms are more efficient than bulk atoms in attaining low energy configurations within the potential energy landscape.
authors.affiliation: Nanomaterials and Microsystems Group, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Sepúlveda
authors.forename: E
authors.initials: E
authors.lastname: Leon-Gutierrez
authors.forename: M
authors.initials: M
authors.lastname: Gonzalez-Silveira
authors.forename: C
authors.initials: C
authors.lastname: Rodríguez-Tinoco
authors.forename: M T
authors.initials: MT
authors.lastname: Clavaguera-Mora
authors.forename: J
authors.initials: J
authors.lastname: Rodríguez-Viejo