QENS insights on the nanoscopic origin of rheological properties in polyethylene oxide based polymer nanocomposites

by Dr Antonio Faraone (NIST)

Monday 20 Jul 2020, 14:30 → 15:30 Europe/Berlin

Zoom Webinar

Polymer nanocomposites (PNCs) with attractive polymer–nanoparticle (NP) interactions, are often reported to disperse individually, enabling the investigation of interfacial effects on the rheological properties without contribution from particle percolation. By taking advantage of selective isotope labeling of the chains, neutron scattering techniques uniquely allow the possibility of investigating the structural and dynamical properties of the polymers in the matrix. We employed high-resolution QuasiElastic Neutron Scattering (QENS) techniques, such as backscattering and Neutron Spin Echo, to directly observe the chain motions at the nanoscale in composites of PolyEthylene Oxide (PEO) with well dispersed silica nanoparticles, Thus we studied both the segmental dynamics at the monomer level and the entangled/collective dynamics at larger scales. The effect of the presence of the NPS on the polymer matrix Rouse dynamics and entanglements explains how both a reinforcing and an unusual softening can be induced in the same material. The results also provide insights on the dynamics of the interphase layer and its persistent mobility even at high nanoparticle loadings.

 

This seminar is held as a Zoom  webinar