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Abstract Electro‐responsive functional materials can play a critical role in selective metal recovery and recycling due to the need for molecular differentiation between transition metals in complex mixtures. Redox‐active metallopolymers are a promising platform for electrochemical separations, offering versatile structural tuning and fast electron transfer. First, through a judicious selection of polymer structure between a main‐chain metallopolymer (polyferrocenylsilane) and a pendant‐group metallopolymer (polyvinylferrocene), charge‐transfer interactions and binding strength toward competing metal ions are tuned, which as a result, dictate selectivity. For example, almost an order of magnitude increase in separation factor between chromate and meta‐vanadate can be achieved, depending on polymer structure. Second, these metallopolymer electrodes exhibit potential‐dependent selectivity that can even flip ion preference, based solely on electrical means—indicating a control parameter that is orthogonal to structural modifications. Finally, this work presents a framework for evaluating electrochemical separations in multicomponent ion mixtures and elucidates the underlying charge‐transfer mechanisms resulting in molecular selectivity through a combination of spectroscopy and electronic structure calculations. The findings demonstrate the applicability of redox‐metallopolymers in tailored electrochemical separations for environmental remediation, value‐added metal recovery, waste recycling, and even mining processing.
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Synthesis and characterization of thermoplastic poly(piperazine succinate) metallopolymers coordinated to ruthenium( III ) or iron( III )
Abstract Metal‐containing polymers represent an ever‐expanding frontier of material science. Of the numerous biocompatible ligands used to create a metallopolymer, piperazine‐containing polymers are still in their early development, even though piperazine is a common functional group in drug design and bioengineering scaffolding elements. We report the first synthesis and characterization (with NMR, IR, GPC, UV–vis spectroscopy, and thermal analysis) of two thermoplastic poly(alkyl piperazine succinate) diols with either propyl or hexyl alkane chains bridging the piperazines. These polyester diols were then chain extended with hexamethylene diisocyanate to create highly amorphous polyester urethane thermoplastic polymers. Ru(III) or Fe(III) was then successfully coordinated with these polymers, with approximately 30% of the bulk metallopolymer product becoming 250x the molecular weight of the non‐metal containing polymers. However, coordination of Fe(III), and to a lesser extent Ru(III), to these polypiperazines accelerated the hydrolysis of the polyester linkage in water over 15 days. Thus, these novel polymers are highly biodegradable with Fe(III) metallopolymers hydrolyzing faster than Ru(III) metallopolymers and poly(propyl piperazine succinate) polymers hydrolyzing faster than poly(hexyl piperazine succinate) polymers.
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- Award ID(s):
- 2018678
- PAR ID:
- 10381828
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Polymer Science
- Volume:
- 61
- Issue:
- 6
- ISSN:
- 2642-4150
- Page Range / eLocation ID:
- p. 447-459
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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