Interplay between local dynamics and mechanical reinforcement in glassy polymer nanocomposites

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Interplay between local dynamics and mechanical reinforcement in glassy polymer nanocomposites

Adam P. Holt, Vera Bocharova, Shiwang Cheng, Alexander M. Kisliuk, Georg Ehlers, Eugene Mamontov, Vladimir N. Novikov, and Alexei P. Sokolov

Phys. Rev. Materials 1, 062601(R) – Published 17 November 2017

Abstract

The modification of polymer dynamics in the presence of strongly interacting nanoparticles has been shown to significantly change the macroscopic properties above the glass transition temperature of polymer nanocomposites (PNCs). However, much less attention has been paid to changes in the dynamics of glassy PNCs. Analysis of neutron and light scattering data presented herein reveals a surprising enhancement of local dynamics, e.g., fast picosecond and secondary relaxations, in glassy PNCs accompanied with a strengthening of mechanical modulus. We ascribe this counter-intuitive behavior to the complex interplay between chain packing and stretching within the interfacial layer formed at the polymer-nanoparticle interface.

Received 24 August 2017
Revised 11 October 2017

DOI:https://doi.org/10.1103/PhysRevMaterials.1.062601

Physics Subject Headings (PhySH)

Polymer glasses Polymer-nanoparticle composites

Brillouin scattering & spectroscopy Dielectric spectroscopy Quasi elastic neutron scattering

Polymers & Soft MatterCondensed Matter, Materials & Applied Physics

Authors & Affiliations

Adam P. Holt^1,†, Vera Bocharova^2,‡, Shiwang Cheng², Alexander M. Kisliuk², Georg Ehlers³, Eugene Mamontov⁴, Vladimir N. Novikov⁵, and Alexei P. Sokolov^1,2,5

¹Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
²Chemical Sciences Division, Oak Ridge National Laboratory Oak Ridge, Tennessee 37831, USA
³Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
⁴Chemical & Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
⁵Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA

^*adam.holt.ctr@nrl.navy.mil
^†Present Address: Naval Research Laboratory, Chemistry Division, Code 6100, Washington, DC 20375–5342, USA.
^‡bocharovav@ornl.gov