Two-population rouse models for polymer segmental dynamics in nanocomposites

Rooks, J. R.*; Ferraro, G.*; Fratini, E.*; Osti, N. C.*; Osawa, Takahito; Faraone, A.*; Wagner, N. J.*

Physical Review E, 113(1), p.015405_1 - 015405_7, 2026/01

https://doi.org/10.1103/s8k6-cvfr

Segmental dynamics of polymer chains in a model nanocomposite of poly(ethylene oxide) and silica nanoparticles (NPs) was investigated using quasi-elastic neutron scattering. Both these dynamics can be accurately described with the Rouse model. The bulk-like polymer far from the NP surface behaves as the neat polymer. However, the slower polymer in the interface close to the NP surface is described either with a second Rouse population with different relaxation time or using the suppressed Rouse model. These simple two-population models accurately reproduce the experimental data, with the suppressed Rouse model describing topological constraints on average every 12 beads with an interfacial thickness up to 13.5 beads, and the effect of the interface extending to a layer of thickness comparable to the end-to-end distance of the polymer.