Nanoparticle-polymer composites, or polymer-nanoparticle composites (PNCs), exhibit unusual mechanical and dynamical features when the particle size approaches the random coil dimensions of the host polymer. Here, we harness favourable enthalpic interactions between particle-tethered and free, host polymer chains to create model PNCs, in which spherical nanoparticles are uniformly dispersed in high molecular weight entangled polymers. Investigation of the mechanical properties of these model PNCs reveals that the nanoparticles have profound effects on the host polymer motions on all timescales. On short timescales, nanoparticles slow-down local dynamics of the host polymer segments and lower the glass transition temperature. On intermediate timescales, where polymer chain motion is typically constrained by entanglements with surrounding molecules, nanoparticles provide additional constraints, which lead to an early onset of entangled polymer dynamics. Finally, on long timescales, nanoparticles produce an apparent speeding up of relaxation of their polymer host.
|Original language||English (US)|
|State||Published - Jun 5 2015|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS–C1018–02
Acknowledgements: This work was supported by the National Science Foundation, Award No. DMR–1006323 and by Award No. KUS–C1018–02, made by the King Abdullah University of Science and Technology (KAUST). Use of the Advanced Photon Source, operated by the Argonne National Laboratory, was supported by the US DOE under Contract No. DE–AC02–06CH11357. We acknowledge Mr Xiaobing Zuo, Assistant Physicist, Argonne National Laboratory for helpful discussions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.