📍 ICIQ Library

⏰  15:45 h

Thermoplastic Polyurethane Elastomer with Mechano-Responsive Hydrogen-Bonding for Enhanced Strength and Self-Healing

The quest for self-repairing materials that can match the healing and resilience of biological tissues faces a challenge as the processes of self-mending and strengthening have traditionally been incompatible. We introduce a carbonate-based thermoplastic polyurethane elastomer capable of self-healing at 35°C and demonstrating a tensile strength of 43 MPa, comparable to that of footwear soles. This elastomer stands out due to its rich carbonyl group content within soft segments and its fully amorphous nature, which results from limited stacking of hard segments, leading to minimal phase separation. It features a unique dual mechano-responsive mechanism that allows for a reversible transition from a disordered to an ordered state in its hydrogen-bonding network, facilitating self-healing in a static state and toughening when in motion. In its static form, the dynamic rearrangement of disordered carbonyl hydrogen bonds in the non-crystalline hard segments enables self-repair. Upon stretching, the amorphous phase transitions into stiff crystals, organizing inter-chain hydrogen bonds. This transformation reverses once the stress is removed, allowing the material to revert to its original state and readying it for subsequent healing cycles.