Abstract
Ionic assemblies, or clusters, determine the structure and dynamics of ionizable polymers and enable their many applications. Fundamental to attaining well-defined materials is controlling the balance between the van der Waals interactions that govern the backbone behavior and the forces that drive the formation of ionic clusters. Here, using small-angle neutron scattering and fully atomistic molecular dynamics simulations, the structure of a model ionomer, sulfonated polystyrene in toluene solutions, was investigated as the cluster cohesion was tweaked by the addition of ethanol. The static structure factor was measured by both techniques and correlated with the size of the ionic clusters as the polymer concentration was varied. The conjunction of SANS results and molecular insight from MD simulations enabled the determination of the structure of these inhomogeneous networks on multiple length scales. We find that across the entire concentration range studied, a network driven by the formation of ionic clusters was formed, where the size of the clusters drives the inhomogeneity of these systems. Tweaking the ionic clusters through the addition of ethanol impacts the packing of the sulfonated groups, their shape, and their size distribution, which, in turn, affects the structure of these networks.
| Original language | English |
|---|---|
| Pages (from-to) | 1688-1698 |
| Number of pages | 11 |
| Journal | Macromolecules |
| Volume | 57 |
| Issue number | 4 |
| DOIs | |
| State | Published - Feb 27 2024 |
Funding
D.P. gratefully acknowledges DOE grant DE-SC0019284 for support. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This work benefited from the use of the SasView application, originally developed under NSF award DMR-0520547. SasView contains code developed with funding from the European Union’s Horizon 2020 research and innovation program under the SINE2020 project, grant agreement No 654000. The authors kindly acknowledge the use of computational resources provided by NSF MRI-1725573. This work was made possible in part by advanced computational resources deployed and maintained by Clemson Computing and Information Technology. This research used resources at the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under contract no. DE-AC02-05CH11231. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. DOEs National Nuclear Security Administration under contract no. DENA-0003525. The views expressed in this article do not necessarily represent the views of the U.S. DOE or the United States Government.
| Funders | Funder number |
|---|---|
| Clemson Computing and Information Technology | |
| National Science Foundation | DMR-0520547 |
| U.S. Department of Energy | DE-SC0019284 |
| Office of Science | DE-AC02-05CH11231 |
| National Nuclear Security Administration | DENA-0003525 |
| Horizon 2020 Framework Programme | 654000 |