Reversibly Cross-Linked Damage-Tolerant Polymers Breaking the Strength-Stretchability Trade-Off

Area of Science:

• Polymer Science
• Materials Science
• Mechanical Engineering

Background:

• Achieving high stretchability and mechanical robustness in polymers is crucial for advanced applications.
• Damage tolerance is essential for polymer reliability, preventing failure under extreme deformation.
• The trade-off between polymer stretchability and strength, especially with damage tolerance, remains a significant challenge.

Purpose of the Study:

• To develop scalable fabrication methods for super-stretchable polymers.
• To achieve polymers with exceptional mechanical robustness and damage tolerance.
• To investigate the mechanisms behind extreme stretchability and sustained mechanical properties.

Main Methods:

• Cross-linking soft polymer chains using synergistic urea-based hydrogen bonding and hydrophobic interactions.
• Characterizing polymer properties including elongation, stress, strain, and fracture energy.
• Analyzing the role of noncovalent cross-link dynamics and polymer chain orientation.

Main Results:

• Fabricated super-stretchable polymers with elongations up to ~100,000 times their original length.
• Achieved high extensional true stress (35.0 MPa at 33.6 strain) and fracture energy (>374.8 kJ m⁻²).
• Demonstrated mechanisms of extreme stretchability via reversible noncovalent cross-link dynamics and strain-induced hydrogen bond transitions.

Conclusions:

• Synergistic noncovalent cross-linking enables polymers with unprecedented stretchability, robustness, and damage tolerance.
• Reversibly cross-linked polymers exhibit self-healing and reprocessability, enhancing sustainability.
• These materials offer significant potential for highly deformable applications requiring robustness and reliability.