On the equivalence between the thermodynamic and dynamic measurements of the glass transition in confined polymers

Rodney D. Priestley, Daniele Cangialosi, Simone Napolitano

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

Understanding why the glass transition temperature (Tg) of polymers deviates substantially from the bulk with nanoscale confinement has been a 20-year mystery. Ever since the observation in the mid-1990s that the Tg values of amorphous polymer thin films are different from their bulk values, efforts to understand this behavior have intensified, and the topic remains the subject of intense research and debate. This is due to the combined scientific and technological implications of size-dependent glassy properties. Here, we discuss an intriguing aspect of the glassy behavior of confined amorphous polymers. As experimentally assessed, the glass transition is a dynamic event mediated by segmental dynamics. Thus, it seems intuitive to expect that a change in Tg due to confinement necessitates a corresponding change in molecular dynamics, and that such change in dynamics may be predicted based on our understanding of the glass transition. The aim of this perspectives article is to examine whether or not segmental dynamics change in accordance with the value of Tg for confined polymers based on bulk rules. We highlight past and recent findings that have examined the relationship between Tg and segmental dynamics of confined polymers. Within this context, the decoupling between these two aspects of the glass transition in confinement is emphasized. We discuss these results within the framework of our current understanding of the glass transition as well as efforts to resolve this decoupling. Finally, the anomalous decoupling between translational (diffusion) and rotational (segmental) motion taking place in the proximity of attractive interfaces in polymer thin films is discussed.

Original languageEnglish (US)
Pages (from-to)288-295
Number of pages8
JournalJournal of Non-Crystalline Solids
Volume407
DOIs
StatePublished - Jan 1 2015

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry

Keywords

  • Chain adsorption
  • Free volume
  • Glass transition
  • Polymer thin films

Fingerprint Dive into the research topics of 'On the equivalence between the thermodynamic and dynamic measurements of the glass transition in confined polymers'. Together they form a unique fingerprint.

Cite this