Mechano-responsive hydrogen-bonding array of thermoplastic polyurethane elastomer captures both strength and self-healing

Abstract

Self-repairable materials strive to emulate curable and resilient biological tissue; however, their performance is currently insufficient for commercialization purposes because mending and toughening are mutually exclusive. Herein, we report a carbonate-type thermoplastic polyurethane elastomer that self-heals at 35 °C and exhibits a tensile strength of 43 MPa; this elastomer is as strong as the soles used in footwear. Distinctively, it has abundant carbonyl groups in soft-segments and is fully amorphous with negligible phase separation due to poor hard-segment stacking. It operates in dual mechano-responsive mode through a reversible disorder-to-order transition of its hydrogen-bonding array; it heals when static and toughens when dynamic. In static mode, non-crystalline hard segments promote the dynamic exchange of disordered carbonyl hydrogen-bonds for self-healing. The amorphous phase forms stiff crystals when stretched through a transition that orders inter-chain hydrogen bonding. The phase and strain fully return to the pre-stressed state after release to repeat the healing process.

Highly thermoconductive yet ultraflexible polymer composites with superior mechanical properties and autonomous self-healing functionalityviaa binary filler strategy

“…3f). 39,44–51 To gain a deep insight into the toughening mechanism, energy dissipation efficiencies were measured using loading–unloading tensile tests. Stretching–retracting cycles at different strains for PUUE and BNNSs 27 –LM 27 /PUUEC are shown in Fig.…”

Near-Infrared-Light-Assisted Self-Healing Graphene-Thermopolyurethane Composite Films

“…Self-healing TPU is capable of re-establishing micro-/macro- cracks by a temporary native rise in the movement of chains of TPU. These behaviors on the TPU mainly depend on the specific molecular chains, which enable the motion of the intermolecular chain, with the application of some measures of energy in the forms of temperature, light, etc., resulting in the restoration of internal chemical and physical strength [ 32 , 33 ]. Self-healing TPU not only retains the advantages of TPU after it is healed and demonstrates excellent self-healing performance under external stimuli (light, heat, pH and force, etc.)…”

“…Self-healing TPU not only retains the advantages of TPU after it is healed and demonstrates excellent self-healing performance under external stimuli (light, heat, pH and force, etc.) [ 11 , 30 , 31 , 32 , 33 ]. TPU’s inherent machinability makes it an excellent carrier for a variety of assembly devices, such as sensors, electronic skin, coatings and biological devices, etc.…”

All‐Around Universal and Photoelastic Self‐Healing Elastomer with High Toughness and Resilience

“…Since the appearance of self‐healing polymers, variety nonautonomous and autonomous design strategies have been developed. [ 9 , 10 , 11 , 12 , 13 ] Self‐healing mechanisms relying on encapsulated or microvascular networks containing healing agents may find a specific limited use for mechanically robust soft systems but their use more generally poses apparent challenges. [ 3 , 14 , 15 ] A more promising strategy has been to use polymeric systems healing on an energy input trigger or autonomously without intervention.…”