The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Free volume dilatation in polymers by ortho-positronium.

På svenska

Author

  • Petra Winberg
  • Morten Eldrup
  • Frans Maurer

Summary, in English

The possibility of positronium induced free volume cavity expansion in some polymers above the glass transition temperature was investigated using experimental positron annihilation lifetime data from the literature for polydimethylsiloxane, polyisobutylene, and polybutadiene as function of temperature. The results suggest that free volume sites can expand towards an equilibrium size, determined as the equilibrium Ps-bubble size defined earlier for low-molecular-weight liquids. The expansion can be explained by the increase of molecular mobility and hence decrease of relaxation times, which at the higher temperatures approach the o-Ps lifetimes. Nanoscale viscosities were estimated using Navier-Stokes equation and were found to be several orders of magnitude lower than the macroscopic viscosity at the same temperature.

Publishing year

2012

Language

English

Publication/Series

Journal of Chemical Physics

Volume

136

Issue

24

Document type

Journal article

Publisher

American Institute of Physics (AIP)

Topic

  • Chemical Sciences

Status

Published

ISBN/ISSN/Other

  • ISSN: 0021-9606