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Globally Suppressed Dynamics in Ion-Doped Polymers

Webb, Michael A. and Yamamoto, Umi and Savoie, Brett M. and Wang, Zhen-Gang and Miller, Thomas F., III (2018) Globally Suppressed Dynamics in Ion-Doped Polymers. ACS Macro Letters, 7 (6). pp. 734-738. ISSN 2161-1653. http://resolver.caltech.edu/CaltechAUTHORS:20180606-124846827

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Abstract

We investigate how ion–polymer complexation suppresses molecular motion in conventional polymer electrolytes using molecular dynamics (MD) simulations of lithium hexafluorophosphate in poly(ethylene oxide) and a modified Rouse model. The employed model utilizes an inhomogeneous friction distribution to describe ion–polymer interactions and provides an effective way to examine how ion–polymer interactions affect polymer motion. By characterizing the subdiffusive Li^+ transport and polymer relaxation times at several salt concentrations, we observe that increases in local friction due to ion-polymer complexation are significantly smaller than previously assumed. We find that a Rouse-based model that only considers local increases in friction cannot simultaneously capture the magnitude of increased polymer relaxation times and the apparent power-law exponent for Li^+ subdiffusion observed in MD simulations. This incompatibility is reconciled by augmenting the modified Rouse model with a term that increases the global friction with the square of the salt concentration; this significantly improves the agreement between the model and MD, indicating the importance of ion–ion interactions and distributions on ion/polymer mobility.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://dx.doi.org/10.1021/acsmacrolett.8b00237DOIArticle
https://pubs.acs.org/doi/suppl/10.1021/acsmacrolett.8b00237PublisherSupporting Information
ORCID:
AuthorORCID
Webb, Michael A.0000-0002-7420-4474
Savoie, Brett M.0000-0002-7039-4039
Wang, Zhen-Gang0000-0002-3361-6114
Miller, Thomas F., III0000-0002-1882-5380
Additional Information:© 2018 American Chemical Society. Received: March 30, 2018; Accepted: June 4, 2018; Published: June 6, 2018. This research was supported by the National Science Foundation under DMREF Award Number NSF-CHE-1335486. M.A.W. also acknowledges support from the Resnick Sustainability Institute. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. The authors declare no competing financial interest.
Group:Resnick Sustainability Institute
Funders:
Funding AgencyGrant Number
NSFCHE-1335486
Resnick Sustainability InstituteUNSPECIFIED
Department of Energy (DOE) DE-AC05-00OR22725
Record Number:CaltechAUTHORS:20180606-124846827
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180606-124846827
Official Citation:Globally Suppressed Dynamics in Ion-Doped Polymers. Michael A. Webb, Umi Yamamoto, Brett M. Savoie, Zhen-Gang Wang, and Thomas F. Miller, III. ACS Macro Letters 2018 7 (6), 734-738. DOI: 10.1021/acsmacrolett.8b00237
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86845
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:06 Jun 2018 20:52
Last Modified:05 Jul 2018 18:24

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