Dynamics near Free Surfaces and the Glass Transition in Thin Polymer Films: A View to the Future

TitleDynamics near Free Surfaces and the Glass Transition in Thin Polymer Films: A View to the Future
Publication TypeJournal Article
Year of Publication2014
AuthorsEdiger, M. D., and J. A. Forrest
JournalMacromolecules
Volume47
Issue2
Start Page471
Date Published01/2014
AbstractThe past 20 years have seen a substantial effort to understand dynamics and the glass transition in thin polymer films. In this Perspective, we consider developments in this field and offer a consistent interpretation of some major findings. We discuss recent experiments that directly measure mobility at or near the surface of glassy polymers. These experiments indicate that enhanced mobility near the free surface can exceed bulk mobility by several orders of magnitude and extend for several nanometers into the bulk polymer. Enhanced mobility near the free surface allows a qualitative understanding of many of the observations of a reduced glass transition temperature Tg in thin films. For thin films, knowledge of Tg by itself is less useful than for bulk materials. Because of this, new experimental methods that directly measure important material properties are being developed.
DOI10.1021/ma4017696