Abstract
Physical networks formed by ionizable polymers with ionic clusters as crosslinks are controlled by coupled dynamics that transcend from ionic clusters through chain motion to macroscopic response. Here, the coupled dynamics, across length scales, from the ionic clusters to the networks in toluene swollen polystyrene sulfonate networks, were directly correlated, as the electrostatic environment of the physical crosslinks was altered. The multiscale insight is attained by coupling neutron spin echo measurements with molecular dynamics simulations, carried out to times typical of relaxation of polymers in solutions. The experimental dynamic structure factor is in outstanding agreement with the one calculated from computer simulations, as the networks are perturbed by elevating the temperature and changing the electrostatic environment. In toluene, the long-lived clusters remain stable over hundreds of ns across a broad temperature range, while the polymer network remains dynamic. Though the size of the clusters changes as the dielectric constant of the solvent is modified through the addition of ethanol, they remain stable but morph, enhancing the polymer chain dynamics.
| Original language | English |
|---|---|
| Article number | 034501 |
| Journal | Physical Review E - Statistical, Nonlinear, and Soft Matter Physics |
| Volume | 109 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2024 |
Funding
D.P. gratefully acknowledges DOE Grant No. DE-SC0019284 for support. NSE measurements were carried out at ORNL's spallation neutron source. The authors gratefully acknowledge the use of computational resources provided by NSF Grant No. 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 using NERSC Award No. BES-ERCAP-0020938. 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. DE-NA-0003525. The views expressed in this paper do not necessarily represent the views of the U.S. DOE or the United States Government.