Self-healing and thermoreversible rubber from supramolecular assembly

Area of Science:

• Materials Science
• Polymer Chemistry
• Supramolecular Chemistry

Background:

• Rubbers exhibit remarkable extensibility and shape recovery due to macromolecular networks.
• Conventional rubbers rely on covalent cross-links or physical associations to prevent flow and creep.
• Existing self-healing and recyclable materials often involve complex synthesis or limited properties.

Purpose of the Study:

• To design and synthesize novel molecular systems capable of forming both polymer chains and cross-links via hydrogen bonds.
• To investigate the mechanical properties, including extensibility and creep resistance, of these hydrogen-bonded materials.
• To evaluate the self-healing capabilities and recyclability of the synthesized materials at room temperature.

Main Methods:

• Synthesis of molecules designed to form supramolecular networks through hydrogen bonding.
• Mechanical testing to determine extensibility (up to several hundred percent) and creep under load.
• Assessment of self-healing efficiency by fracturing and rejoining samples at room temperature.
• Evaluation of recyclability and processability.

Main Results:

• Successfully designed and synthesized molecules that self-assemble into hydrogen-bonded networks, mimicking rubber elasticity.
• Achieved recoverable extensibility up to several hundred percent with minimal creep under load.
• Demonstrated efficient self-healing at room temperature upon fracture, with full recovery of mechanical properties.
• Confirmed the ability to repeat the breaking and healing process multiple times, indicating excellent durability and recyclability.

Conclusions:

• Hydrogen-bonded molecular systems can effectively replicate the properties of conventional rubbers, including high extensibility and elasticity.
• These novel materials exhibit unprecedented self-healing capabilities at room temperature, enabling facile repair and reuse.
• The straightforward synthesis from renewable resources (fatty acids and urea) and low cost suggest significant potential for sustainable material applications.