Atomic scattering as a probe of polymer surface and thin film dynamics

M. A. Freedman, A. W. Rosenbaum, S. J. Sibener

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Collisional energy transfer at the surface of poly(methyl methacrylate) thin films on Si Ox Si was investigated using low-energy neutral helium atom scattering. Analysis of spectra in two scattering regimes yields results consistent with the hypothesis that thinner films are stiffer, suggesting that for highly nanoconfined films, polymer-substrate interactions influence vibrational dynamics at the polymer-vacuum interface. Specifically, thinner films are found to have lower mean-square displacements and decreased annihilation events as compared to thicker films. The scattering spectra are fit well by a semiclassical scattering model, though deviations arise at sample temperatures near the bulk glass transition. We have found helium atom scattering to be a sensitive probe of the vibrational dynamics of the polymer thin film surface. This technique holds promise for the exploration of glassy dynamics of polymer thin films.

Original languageEnglish (US)
Article number113410
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume75
Issue number11
DOIs
StatePublished - Mar 29 2007

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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