Arora, Swati
(2023)
Understanding the Dynamics of Ion Locking in Doubly-Polymerized Ionic Liquids.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Controlling the dynamics of ion motion in polymerized ionic liquids remains enticing for the development of advanced organic electronics.1,2 Previous studies have extensively reported ion dynamics in singly polymerized ionic liquids (SPILs).3-7 However, a lot needs to be uncovered with regards to a molecular-level understanding of dynamics in “doubly polymerized” ionic liquids, or DPILs, in which both ionic species are covalently linked to polymer chains.8-11 Polymerizing both the ionic species in an ionic liquid drastically decreases the ionic conductivity and locks the ions in place. While intentionally restricting the ion motion may be counterintuitive, given that a large focus of the polymerized ionic liquid community has so far been optimizing ion transport without sacrificing mechanical properties, it has been recently shown that “locking” ions in place in polymeric materials can actually enable new classes of organic electronics, which has been an important motivation for our work.12,13
A significantly deeper fundamental understanding, however, is needed to examine the factors that influence the time duration until which the ions can be locked in a place called the “electric double layer” (EDL) retention time. To investigate these questions, we characterized these materials using Broadband dielectric spectroscopy (BDS) over a broad frequency and temperature range.
The dielectric studies demonstrate that the polymerization of both the ionic species in DPIL not only radically reduces the bulk conductivities of the material significantly, but also slows the relaxation timescales corresponding to ionic rearrangement by more than four orders of magnitude relative to SPILs which we attributed to ionic interactions effectively forming physical crosslinks between the polymer chains.
Understanding the fundamental mechanisms of ion locking in these materials, and using this knowledge to inform design rules for the tunable functional devices, will be critical in moving these applications forward. Thus, this study will stimulate advances in investigating the fundamental properties of ion-containing polymers and developing DPIL as promising materials in novel device applications.
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| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
24 January 2023 |
| Date Type: |
Publication |
| Defense Date: |
2 August 2022 |
| Approval Date: |
24 January 2023 |
| Submission Date: |
15 August 2022 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
164 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Doubly-Polymerized Ionic Liquids |
| Date Deposited: |
24 Jan 2023 16:18 |
| Last Modified: |
24 Jan 2023 16:18 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/43622 |
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