2D Covalent Organic Framework Membranes for Liquid-Phase Molecular Separations: State of the Field, Common Pitfalls, and Future Opportunities

David W. Burke, Zhiwei Jiang, Andrew G. Livingston*, William R. Dichtel*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

50 Scopus citations

Abstract

2D covalent organic frameworks (2D COFs) are attractive candidates for next-generation membranes due to their robust linkages and uniform, tunable pores. Many publications have claimed to achieve selective molecular transport through COF pores, but reported performance metrics for similar networks vary dramatically, and in several cases the reported experiments are inadequate to support such conclusions. These issues require a reevaluation of the literature. Published examples of 2D COF membranes for liquid-phase separations can be broadly divided into two categories, each with common performance characteristics: polycrystalline COF films (most >1 µm thick) and weakly crystalline or amorphous films (most <500 nm thick). Neither category has demonstrated consistent relationships between the designed COF pore structure and separation performance, suggesting that these imperfect materials do not sieve molecules through uniform pores. In this perspective, rigorous practices for evaluating COF membrane structures and separation performance are described, which will facilitate their development toward molecularly precise membranes capable of performing previously unrealized chemical separations. In the absence of this more rigorous standard of proof, reports of COF-based membranes should be treated with skepticism. As methods to control 2D polymerization improve, precise 2D polymer membranes may exhibit exquisite and energy efficient performance relevant for contemporary separation challenges.

Original languageEnglish (US)
Article number2300525
JournalAdvanced Materials
Volume36
Issue number1
DOIs
StatePublished - Jan 4 2024

Funding

D.W.B. and W.R.D. acknowledge support from the National Science Foundation (087147\u201016468\u201001//CBET\u20101706219) and the Northwestern University Materials Research Science and Engineering Center (NSF DMR\u20101720139\u2010005). Z.J. acknowledges support from UK Research and Innovation Future Leaders Fellowships [MR/W009382/1]. A.G.L. acknowledges support from the European Research Council, Advanced Grant number 786398. D.W.B. and W.R.D. acknowledge support from the National Science Foundation (087147-16468-01//CBET-1706219) and the Northwestern University Materials Research Science and Engineering Center (NSF DMR-1720139-005). Z.J. acknowledges support from UK Research and Innovation Future Leaders Fellowships [MR/W009382/1]. A.G.L. acknowledges support from the European Research Council, Advanced Grant number 786398.

Keywords

  • 2D polymers
  • covalent organic frameworks
  • membranes
  • polymer thin films

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint

Dive into the research topics of '2D Covalent Organic Framework Membranes for Liquid-Phase Molecular Separations: State of the Field, Common Pitfalls, and Future Opportunities'. Together they form a unique fingerprint.

Cite this