In Situ Photopolymerization of Hydrogels in Radical Covalent Organic Frameworks

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Traditional molecular photoinitiators in hydrogel synthesis face limitations.
• Issues include migration, poor photostability, limited functionality, and weak mechanical properties.

Purpose of the Study:

• To introduce macromolecular radical covalent organic frameworks (COFs) as advanced photoinitiating agents for hydrogel synthesis.
• To investigate the dual-initiation mechanism and resulting hydrogel properties.

Main Methods:

• Synthesis of radical covalent organic frameworks (COFs).
• In situ polymerization within the COF matrix.
• Characterization of hydrogel mechanical properties (tensile strength, stretchability, toughness).

Main Results:

• Hydrogels synthesized using radical COFs exhibit ultrahigh tensile strength (4.3 MPa).
• Achieved outstanding stretchability (13,382% fracture strain) and exceptional toughness (262 MJ/m³).
• Demonstrated fully recoverable large deformation up to 1500% strain.

Conclusions:

• Macromolecular COFs serve as effective next-generation photoinitiators for high-performance hydrogels.
• The enhanced properties are attributed to nanoconfinement and chemical crosslinking.
• These robust hydrogels show promise for wearable sensors requiring high sensitivity and durability.