title: Structural relaxations of thin polymer films.
abstract: Time-dependent changes of thermodynamic properties due to structural relaxations and physical aging occur in all glasses. We show that the physical aging of thin supported films of star-shaped macromolecules, with f arms of length N(arm), exhibits average aging dynamics that are sensitive to f and N(arm). Regions of the films in proximity to interfaces age at substantially different rates than the interior of the film; this is also true of linear chain systems. This behavior may be reconciled in terms of a universal picture that accounts only for changes in the local T(g) of the films.
authors.affiliation: Macromolecular Science and Engineering Program, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Bradley
authors.initials: B
authors.lastname: Frieberg
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Glynos
authors.forename: Peter F
authors.initials: PF
authors.lastname: Green