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

• DOI: 10.1038/s41467-021-20931-z
• Publication Date: 2021-01-27T11:06:38Z
• Authors: Youngho Eom; Seon-Mi Kim; Minkyung Lee; Hyeonyeol Jeon; Jaeduk Park; Eun Seong Lee; Sung Yeon Hwang; Jeyoung Park; Dongyeop X. Oh
• Keywords: Science; Q; 02 engineering and technology; 0210 nano-technology; Article

AbstractSelf-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.