Hydrophilic domain structure in polymer exchange membranes: Simulations of NMR spin diffusion experiments to address ability for model discrimination
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Organic Material Science
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Computational Material and Data Science; NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States). Thermal Protection Materials Branch; Analytical Mechanics Associates, Inc., Hampton, VA (United States)
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Computational Material and Data Science
Here, we detail the development of a flexible simulation program (NMR_DIFFSIM) that solves the nuclear magnetic resonance (NMR) spin diffusion equation for arbitrary polymer architectures. The program was used to explore the proton (1H) NMR spin diffusion behavior predicted for a range of geometrical models describing polymer exchange membranes. These results were also directly compared with the NMR spin diffusion behavior predicted for more complex domain structures obtained from molecular dynamics (MD) simulations. The numerical implementation and capabilities of NMR_DIFFSIM were demonstrated by evaluating the experimental NMR spin diffusion behavior for the hydrophilic domain structure in sulfonated Diels-Alder Poly(Phenylene) (SDAPP) polymer membranes. The impact of morphology variations as a function of sulfonation and hydration level on the resulting NMR spin diffusion behavior were determined. These simulations allowed us to critically address the ability of NMR spin diffusion to discriminate between different structural models, and to highlight the extremely high fidelity experimental data required to accomplish this. A direct comparison of experimental double-quantum-filtered 1H NMR spin diffusion in SDAPP membranes to the spin diffusion behavior predicted for MD-proposed morphologies revealed excellent agreement, providing experimental support for the MD structures at low to moderate hydration levels.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
- Grant/Contract Number:
- AC04-94AL85000; NA0003525
- OSTI ID:
- 1472249
- Report Number(s):
- SAND-2018-9547J; 667473
- Journal Information:
- Journal of Polymer Science. Part B, Polymer Physics, Vol. 56, Issue 1; ISSN 0887-6266
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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