An ultralow-temperature superelastic polymer aerogel with high strength as a great thermal insulator under extreme conditions

In extremely low-temperature environments such as aerospace and polar regions, advanced elastic thermal insulation materials are urgently needed but their development is challenging, as traditional elastic insulators are completely frozen, lose elasticity and become brittle. Herein, we proposed a novel structural elastic strategy to create an ultralow-temperature elastic polymer aerogel with highly oriented thin nanosheets and hierarchically honeycomb-like architectures from low-cost raw materials. This approach endowed the polymer aerogel with superelasticity and high strength at liquid nitrogen temperature (-196 degrees C), where the aerogel can bear more than 10 000 times its weight and repeatedly recover to its original size after force removal. The underlying structural elastic mechanism was revealed by finite element simulation calculation. The resultant robust aerogel also displayed an excellent extreme-condition thermal insulation, which could maintain a pleasant interior environment with small temperature changes under harsh external environments from liquid nitrogen to fire scenarios. It combined the great features of ultralow-temperature superelasticity with high mechanical strength, excellent thermal insulation under extremely harsh conditions, fire retardancy, and performance stability. These results provide new insights and general methods for the development of advanced super-elastic polymeric insulators with high strength at ultralow temperatures.