Amphiphilic Reactive Interfaces Enable Controlled Synthesis of Mesoscopic Covalent Organic Frameworks

Area of Science:

• Materials Science
• Nanotechnology
• Supramolecular Chemistry

Background:

• Interfaces are crucial for novel material development but constructing reactive interfaces for crystalline porous materials synthesis is challenging.
• Controlled bottom-up synthesis of advanced porous materials like covalent organic frameworks (COFs) requires sophisticated interface engineering.

Purpose of the Study:

• To develop a stable, morphology-tunable reactive interface for the controlled synthesis of covalent organic frameworks (COFs).
• To achieve diverse mesoscopic architectures and hierarchical porosity in COFs through interface-confined reactions and Pickering emulsion templating.

Main Methods:

• Spontaneous self-assembly of amphiphilic moieties from Schiff base reactions to form surfactant-free reactive interfaces.
• Tuning interface morphology by varying the hydrophobic chain length of aliphatic amines (C4-C12).
• Utilizing colloidal SiO2 nanospheres to form nanoscale Pickering emulsions for hierarchical pore formation.

Main Results:

• A stable, morphology-tunable interface enabling mild, facile, and controlled synthesis of COFs with spherical, ribbon, and sheet architectures.
• Hierarchical porous COFs with tunable large mesopores (17-40 nm) achieved via Pickering emulsion templating.
• Asymmetric hemispherical hollow COFs demonstrated high surface area (561.9 m²/g) and excellent electrochemical performance as iodine hosts.

Conclusions:

• The developed reactive interface strategy offers a versatile platform for controlled COF synthesis with tunable structures and properties.
• Hierarchical porous COFs exhibit potential for advanced applications, particularly in energy storage and host-guest chemistry.
• The method facilitates the creation of materials with enhanced ion transport and active site accessibility due to mesoporosity and asymmetric morphology.