Polymer structure(s) seen by scattering: microgels and nanocomposites
| When |
Jan 17, 2023
from 11:00 to 12:00 |
|---|---|
| Where | R117 |
| Attendees |
Julian Oberdisse |
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Small-angle (neutron) scattering is the perfect tool to study the average conformation of macromolecules in about any environment, from solvents to other polymer molecules. The power of the method is intimately related to the length scale of observation, the virtual absence of artefacts due to the averaging, and most importantly, the possibilities to adjust contrasts and highlight chosen parts of the samples. In this talk, after a (hopefully didactical) introduction, two recent applications will be reviewed.
In collaboration Thomas Hellweg (Bielefeld), we have investigated the internal structure of core-shell microgel particles in suspension. Using selective deuteration, core- and shell monomers could be measured independently, and the corresponding monomer profile described by a reverse Monte Carlo approach [1]. In the second part, an application to polymer nanocomposites will be discussed. Rubber-based nanocomposites show a large variety of spatial organization of the filler nanoparticles, which can be studied by small-angle scattering and analyzed by large-scale reverse Monte Carole simulation [3]. A key feature of rubber nanocomposites is linked to the influence of the filler surfaces on the polymer structure and dynamics [4]. 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, including a peculiar, “fish-shaped” interfacial gradient.
[1] M. Cors, O. Wrede, L. Wiehemeier, A. Feoktystov, F. Cousin, T. Hellweg, J. Oberdisse, Scientific Reports 2019, 9, 13812.
[2] D. Musino, A.-C. Genix, T. Bizien, J. Oberdisse, Nanoscale, 2020, 12, 3907.
[3] A.C. Genix, V. Bocharova, B. Carroll, P. Dieudonné-George, M. Sztucki, R. Schweins, A. P. Sokolov, and J. Oberdisse, ACS Applied Materials and Interfaces 2021, 13, 36262.