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Related Experiment Video

Updated: Feb 18, 2026

Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

Published on: July 10, 2017

Concentration-Directed Polymorphic Surface Covalent Organic Frameworks: Rhombus, Parallelogram, and Kagome.

Yi-Ping Mo^1,2, Xuan-He Liu^1,2, Dong Wang¹

¹CAS Key Laboratory of Molecular Nanostructure and Nanotechnology and CAS Research and Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS) , Beijing 100190, People's Republic of China.

|November 14, 2017

Summary

Researchers synthesized polymorphic single-layered covalent organic frameworks (sCOFs) on surfaces, creating tunable rhombus, parallelogram, and Kagome networks. Dynamic covalent chemistry allows control over network formation, similar to supramolecular assembly principles.

Keywords:

Kagome dynamic covalent bonds monomer concentration scanning tunneling microscopy surface covalent organic frameworks

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Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

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Published on: June 14, 2024

Area of Science:

Materials Science
Surface Chemistry
Nanotechnology

Background:

Covalent organic frameworks (COFs) are crystalline porous polymers.
On-surface synthesis enables precise control over COF structures.
Polymorphism in COFs is crucial for tuning material properties.

Purpose of the Study:

Investigate polymorphic single-layered covalent organic frameworks (sCOFs) synthesized on a surface.
Explore the formation of different network topologies (rhombus, parallelogram, Kagome).
Understand the influence of monomer concentration on COF network distribution.

Main Methods:

On-surface synthesis using a tetradentate pyrene derivative and ditopic linear diamines.
Characterization of sCOF structures using scanning tunneling microscopy (STM).
Statistical analysis of network distribution based on monomer concentration.

Main Results:

Successfully synthesized three types of ordered sCOFs: rhombus, parallelogram, and Kagome networks.
Demonstrated tunability of pore size and periodicity by varying diamine linker length.
Observed a concentration-dependent distribution of network types, with quadrate networks favored at high concentrations and Kagome networks at low concentrations.

Conclusions:

The dynamic covalent reaction and self-sorting behavior enable control over polymorphic sCOF distribution.
Network density differences explain the observed concentration-dependent trends.
On-surface synthesis offers a pathway to design and control polymorphic COF structures for tailored applications.