Surface and bulk dynamics of compressed polystyrene films: A β-NMR study

POSTER

Abstract

Glasses gradually densify as they relax towards equilibrium, and in doing so, their spectral density of molecular fluctuations is modified. In polystyrene (PS), only a few percent increase in density is equivalent to the passage of millions of years. To access this regime, we have plastically deformed a PS thin film with nanoimprint lithography, resulting in permanent compactification without rejuventation1. We present depth-resolved 8Li+ β-NMR measurements in PS films and discuss the dynamical effects of the mechanical processing. β-NMR is a technique sensitive to nanosecond molecular dynamics through the spin-lattice relaxation of a short-lived radioisotope. Because the isotope is implanted as a low-energy ion beam, the depth is controllable with nanometer-scale resolution. This has allowed β-NMR to directly probe the dynamics in glassy polymer thin films near both the free and buried interfaces2.

1 H. D. Rowland et al., Science 322, 720–724 (2008).
2 I. McKenzie et al., Soft Matter 14, 7291–7544 (2018).

Presenters

  • Derek Fujimoto

    • University of British Columbia
    • Physics and Astronomy, University of British Columbia

Authors

  • Derek Fujimoto

    • University of British Columbia
    • Physics and Astronomy, University of British Columbia

  • Owen Brazil

    • Trinity College Dublin

  • Aris Chatzichristos

    • University of British Columbia

  • Martin H Dehn

    • University of British Columbia
    • Physics and Astronomy, University of British Columbia

  • Victoria L. Karner

    • University of British Columbia
    • Chemistry, University of British Columbia

  • Robert F Kiefl

    • University of British Columbia
    • Physics and Astronomy, University of British Columbia

  • Philip C. P. Levy

    • TRIUMF
    • University of British Columbia

  • Ryan M. L. McFadden

    • University of British Columbia
    • Chemistry, University of British Columbia

  • Iain McKenzie

    • TRIUMF

  • Gerald Morris

    • TRIUMF

  • Matt Pearson

    • TRIUMF

  • Monika K Stachura

    • TRIUMF

  • John Ticknor

    • University of British Columbia
    • Chemistry, University of British Columbia

  • W Andrew MacFarlane

    • University of British Columbia
    • Chemistry, University of British Columbia

  • Graham Cross

    • Trinity College Dublin