Morphology of Anion-Conducting Ionenes Investigated by X‑ray Scattering and Simulation

We have studied the morphology of a novel series of benzimidazole-based ionenes, methylated poly­(hexamethyl-p-terphenyl­benzimidazolium) (HMT-PMBI), in halide form. Materials with anion-exchange capacities ranging from 0 to 2.5 mequiv/g were studied. X-ray scattering reveals three length scales in...

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Bibliographic Details
Published in:The journal of physical chemistry. B 2018-02, Vol.122 (5), p.1730-1737
Main Authors: Schibli, Eric M., Wright, Andrew G., Holdcroft, Steven, Frisken, Barbara J.
Format: Article
Language:English
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Summary:We have studied the morphology of a novel series of benzimidazole-based ionenes, methylated poly­(hexamethyl-p-terphenyl­benzimidazolium) (HMT-PMBI), in halide form. Materials with anion-exchange capacities ranging from 0 to 2.5 mequiv/g were studied. X-ray scattering reveals three length scales in the materials: ion–polymer spacing (4 Å), polymer–polymer interchain spacing (6 Å), and an intrachain repeat distance (20 Å). No long-range structure is apparent above the monomer length, which is rare in ion-conducting polymer membranes. In preliminary molecular dynamics simulations, water molecules were observed forming chains between ions, even at a modest level of hydration, providing an interpenetrating network where conductivity can occur.
ISSN:1520-6106
1520-5207
DOI:10.1021/acs.jpcb.7b10177