# COF thin films for molecular separation

> COFs usually come out as insoluble powders. Grown instead where two liquids that do not mix meet, β-ketoenamine COFs form continuous, free-standing films under ambient conditions; they can be lifted onto any support and made thinner than 100 nm. Tp-Bpy, from Tp and a bipyridine diamine, has a surface area of 1151 m² g⁻¹ and lets acetonitrile through at 339 L m⁻² h⁻¹ bar⁻¹ while holding dissolved molecules back.

- Page: https://www.labcanvas.com/templates/covalent-organic-frameworks/cof-thin-film-membranes-interfacial-crystallization
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- Updated: 2026-10-14
- Category: Covalent organic frameworks
- Method: Interfacial crystallization, bottom-up
- Starting materials: Tp (1,3,5-triformylphloroglucinol) and 2,2′-bipyridine-5,5′-diamine, each in one of two liquids that do not mix
- Product: Free-standing, crystalline, porous Tp-Bpy films, transferable onto any substrate
- Key result: Tp-Bpy: BET surface area 1151 m² g⁻¹; acetonitrile permeance 339 L m⁻² h⁻¹ bar⁻¹; high chemical and thermal stability (Dey et al. 2017)
- Figure: 1920 × 1080 px, 76 editable layers (10 generated objects with settings)

## Steps

1. **Two liquids**: The two monomers start in separate liquids that do not mix
2. **Interface**: They meet and react only at the liquid–liquid interface, under ambient conditions
3. **Free-standing film**: A continuous crystalline film grows without any support; thickness can be tuned down to sub-100 nm
4. **Transfer**: Lifted off and laid on any desired substrate
5. **Separation**: Solvent passes; dissolved molecules are held back (Dey et al. 2017)

## Strengths

- Processable films instead of powders
- Ordered pores of one size
- Chemically robust β-ketoenamine links

## Limitations

- Large, defect-free films are hard to make
- Pores of 2D COFs are larger than small solutes

## Uses

- Organic solvent nanofiltration
- Dye removal
- Membranes and coatings

## References

1. Dey et al., “Selective Molecular Separation by Interfacially Crystallized Covalent Organic Framework Thin Films”, J. Am. Chem. Soc. 2017. https://doi.org/10.1021/jacs.7b06640 (primary)
2. Kandambeth et al., “Construction of Crystalline 2D Covalent Organic Frameworks with Remarkable Chemical (Acid/Base) Stability via a Combined Reversible and Irreversible Route”, J. Am. Chem. Soc. 2012. https://doi.org/10.1021/ja308278w (further reading)
3. Geng et al., “Covalent Organic Frameworks: Design, Synthesis, and Functions”, Chem. Rev. 2020. https://doi.org/10.1021/acs.chemrev.9b00550 (review)

Credit: After Dey et al., JACS 2017 (doi:10.1021/jacs.7b06640) and Kandambeth et al., JACS 2012 (doi:10.1021/ja308278w). Layer drawn from bond lengths; film and filtration cell schematic.

## Questions

**What does the “COF thin films for molecular separation” template show?** COFs usually come out as insoluble powders. Grown instead where two liquids that do not mix meet, β-ketoenamine COFs form continuous, free-standing films under ambient conditions; they can be lifted onto any support and made thinner than 100 nm. Tp-Bpy, from Tp and a bipyridine diamine, has a surface area of 1151 m² g⁻¹ and lets acetonitrile through at 339 L m⁻² h⁻¹ bar⁻¹ while holding dissolved molecules back.

**What are the steps shown in “COF thin films for molecular separation”?** 1. Two liquids: The two monomers start in separate liquids that do not mix. 2. Interface: They meet and react only at the liquid–liquid interface, under ambient conditions. 3. Free-standing film: A continuous crystalline film grows without any support; thickness can be tuned down to sub-100 nm. 4. Transfer: Lifted off and laid on any desired substrate. 5. Separation: Solvent passes; dissolved molecules are held back (Dey et al. 2017).

**What are the starting materials and the product?** Starting materials: Tp (1,3,5-triformylphloroglucinol) and 2,2′-bipyridine-5,5′-diamine, each in one of two liquids that do not mix. Product: Free-standing, crystalline, porous Tp-Bpy films, transferable onto any substrate.

**Which papers is “COF thin films for molecular separation” based on?** Dey et al., “Selective Molecular Separation by Interfacially Crystallized Covalent Organic Framework Thin Films”, J. Am. Chem. Soc. 2017 (doi:10.1021/jacs.7b06640); Kandambeth et al., “Construction of Crystalline 2D Covalent Organic Frameworks with Remarkable Chemical (Acid/Base) Stability via a Combined Reversible and Irreversible Route”, J. Am. Chem. Soc. 2012 (doi:10.1021/ja308278w); Geng et al., “Covalent Organic Frameworks: Design, Synthesis, and Functions”, Chem. Rev. 2020 (doi:10.1021/acs.chemrev.9b00550).

**Can I edit the “COF thin films for molecular separation” template?** Yes. Open it in the LabCanvas editor: all 76 layers are editable, including 10 generated objects (structures, plots, equipment) with their own settings. Change the text, colours and layout, then export PNG, TIFF, SVG or PDF.

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