Robust Polymer Films: Nanoscale Stiffening as a Route to Strong Materials

Abstract

Ultrathin polymer films show exceptional property changes that are attributed to the nanoscale confinement of the macromolecules. During the course of the present work (June 2007-August 2011) we have made several discoveries. First, the glass transition temperature can be reduced by over 100 K in the thinnest films we tested and for polycarbonate. This effect, however, is not universal as, for example, poly(vinyl acetate) shows only a weak effect. In addition, we found that the rubbery stiffening of poly(styrene), polycarbonate and poly(vinyl acetate) are similar, with the compliance increasing as the square of the film thickness. However, for poly(n-butyl methacrylate) the response is closer to linear in thickness. Finally, it is also found that the glassy modulus increases by approximately a factor of two-three in the thinnest films.

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Document Details

Document Type
Technical Report
Publication Date
Oct 20, 2011
Accession Number
ADA579266

Entities

People

  • Gregory B. McKenna

Organizations

  • Texas Tech University

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Amorphous Materials
  • Dielectric Polymers
  • Engineering
  • Geometry
  • Glass Transition Temperature
  • Materials
  • Materials Laboratories
  • Materials Science
  • Materials Testing
  • Mechanics
  • Plastics
  • Polymeric Films
  • Polymers
  • Surface Energy
  • Surface Tension
  • Thin Films
  • Transition Temperature

Readers

  • Nanocomposite Materials Science
  • Polymer Science and Engineering.
  • Structural Dynamics.