Low-Temperature Self-Healing Supramolecular Zinc-Poly(Urea–Urethane) Elastomer

Abstract

In the exploration of extreme environments such as polar and outer space, the elastomers used in flexible structures on equipment/facilities tend to harden and brittle, losing deformability and even break. This will cause huge maintenance costs and serious safety risks. To solve this problem, we designed a rapidly, cryogenically self-repairing supramolecular zinc-poly(urea–urethane) elastomer with excellent mechanical properties. The elastomer exhibits excellent flexibility and bends over 90° easily after a period of time in liquid nitrogen (−196 °C). At −90 °C, the elastomer exhibits good ductility and can realize self-repair. In the cantilever mode, the loaded end can produce a displacement of ∼9000 μm under 18 N, which is considerably larger than those of hydroxyl-terminated polybutadiene and polydimethylsiloxane (approximately 95 and 75 μm, respectively). In addition, at −40 °C, the elastomer possesses a high elongation at break of ∼1819.1%, the fastest self-repairing ability among the reported elastomers of similar strength. This supramolecular zinc-poly(urea–urethane) elastomer has a broad application prospect at extremely low temperatures.