Abstract
We have used transmission ellipsometry to perform a comprehensive study of the glass transition temperature of freely standing polystyrene films. Six molecular weights ranging from to were used in the study. For each value, large reductions in (as much as below the bulk value) were observed as the film thickness h was decreased. We have studied in detail the dependence of the reductions on in a regime dominated by chain confinement effects. The empirical analysis presented is highly suggestive of the existence of a mechanism of mobility in thin freely standing films that is inhibited in the bulk and distinct from the usual cooperative motion associated with the glass transition.
- Received 19 January 2000
DOI:https://doi.org/10.1103/PhysRevE.63.031801
©2001 American Physical Society