β-NMR Studies of the Depth Dependence of Secondary Relaxations in Polystyrene Thin Films

ORAL

Abstract

β-detected nuclear magnetic resonance (β-NMR) of implanted 8Li+ has been used to probe the depth dependence of secondary relaxation processes in thin films of atactic polystyrene (PS). β-NMR measurements of the average 8Li spin-lattice relaxation rate were used to determine the depth dependence of the fluctuation rate of the fast γ-relaxation process in PS films at 317 K, which is well below its glass transition temperature [I. McKenzie et al. Soft Matter, 14, 7324 (2018)]. A novel hole-burning (selective saturation) β-NMR technique has been used to measure the depth dependence of the fluctuation rate of the much slower β-relaxation process at the same temperature. Both the fluctuation rates of the β- and γ-relaxation processes are larger near the free surface than in the bulk and both return to the bulk value over a length scale of several nm.

–

Presenters

  • Iain McKenzie

    Physical Sciences Division, TRIUMF

Authors

  • Iain McKenzie

    Physical Sciences Division, TRIUMF

  • Yu Chai

    Lawrence Berkeley National Lab, Physics and Astronomy, University of Waterloo

  • David Cortie

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

  • James Forrest

    Physics and Astronomy, University of Waterloo, University of Waterloo

  • Derek Fujimoto

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

  • Victoria Karner

    Departament of Chemistry, University of British Columbia, Chemistry, University of British Columbia

  • Robert F Kiefl

    Department of Physics and Astronomy, University of British Columbia, Physics and Astronomy, University of British Columbia, Department of Physics & Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia

  • CDP Levy

    Accelerator Division, TRIUMF

  • W Andrew MacFarlane

    Departament of Chemistry, University of British Columbia, Chemistry, University of British Columbia, Department of Chemistry, University of British Columbia

  • Ryan McFadden

    Departament of Chemistry, University of British Columbia, Chemistry, University of British Columbia

  • Gerald D Morris

    Center for Molecular and Materials Science, TRIUMF, Vancouver, BC V6T 2A3, Canada, Physical Sciences Division, TRIUMF, TRIUMF, TRIUMF, Vancouver, British Columbia V6T 2A3, Canada.

  • Matthew Pearson

    Physical Sciences Division, TRIUMF

  • Adam Raegen

    Physics and Astronomy, University of Waterloo, University of Waterloo

  • Shipei Zhu

    Physics and Astronomy, University of Waterloo