Fishing for polymer and nanoparticles in nanocomposites using SANS, SAXS, and simulations.
Résumé
Rubber-based nanocomposites prepared by solid-phase mixing with precipitated silica nanoparticles are typically strongly
aggregated systems with different levels of spatial organization, as highlighted by our group in the past [1]. The strategy
that we developed these past years was to investigate such systems based on the study of simplified industrial samples
with ingredients limited to a strict minimum. The analysis of small-angle X-ray scattering data can then be performed on
the scale of a micrometric simulation box. Tens of thousands of “model” nanoparticles are embedded in the matrix, and
their dispersion strongly affects both the mechanical properties of the material, and the scattered intensity. A statistical
method based on a reverse Monte Carlo solution of this many-parameter scattering problem will be presented, showing
that some key features like percolation can be described [2].
Another key feature of rubber nanocomposites refers to the influence of the filler surfaces on the polymer structure and
dynamics, and some recent progress will be discussed [3]. In particular, we have studied blends of short and long chains,
where one chain type is deuterated, by small-angle neutron scattering. Different degrees of spatial segregation could be
identified recently, including a peculiar, “fish-shaped” interfacial gradient characterized also by reverse Monte Carlo
simulations, this time of the interface.
[1] Guilhem P. Baeza, Anne-Caroline Genix, C. Degrandcourt, Laurent Petitjean, Jérémie Gummel, Marc Couty, Julian Oberdisse, Macromolecules 2013, 46, 317−329
(cover article)
[2] Musino D, Genix A-C, Chauveau E, Bizien T, Oberdisse J, Nanoscale 2020, 12:3907.
[3] A.C. Genix, V. Bocharova, B. Carroll, P. Dieudonné-George, M. Sztucki, R. Schweins, A. P. Sokolov, and Julian Oberdisse, ACS Applied Materials and Interfaces,
2021, in press