title: Effect of atmosphere on reductions in the glass transition of thin polystyrene films.
abstract: We have used nulling ellipsometry to measure the glass transition temperature, T (g) , of thin films of polystyrene in ambient, dry nitrogen, and vacuum environments. For all environments, the measured T (g) values decrease with decreasing film thickness in a way that is quantitatively similar to previously reported studies in ambient conditions. These results provide strong reinforcement of previous conclusions that such reduced T (g) values are an intrinsic property of the confined material. Furthermore, the results are in contrast to recent reports which suggest that the T (g) reductions measured by many researchers are the results of artifacts (i.e. degradation of the polymer due to annealing in ambient conditions, or moisture content).
authors.affiliation: Department of Physics & Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada.
authors.forename: A N
authors.initials: AN
authors.lastname: Raegen
authors.forename: M V
authors.initials: MV
authors.lastname: Massa
authors.forename: J A
authors.initials: JA
authors.lastname: Forrest
authors.forename: K
authors.initials: K
authors.lastname: Dalnoki-Veress