Highly Loaded Actuation Achieved by Shape Memory Block Copolyimide Aerogels with Tunable Distribution of Stationary and Reversible Phases

The need for a new generation of smart materials in aerospace engineering has spurred substantial research into shape memory materials. As one of the newest types, the shape memory polyimide aerogels have shown great potential due to the lightness, high transition temperature, and stability in an extreme environment. Herein, two kinds of amines with different stiffnesses were screened to prepare a series of shape memory block copolyimide aerogels, which demonstrate the amazing shape memory properties. Over five shape memory cycles, the shape fixation and recovery ratio both surpassed 99%; other than that, the as-prepared block copolyimide aerogels showed the swift (less than 4 s) and complete (over 99%) recovery in the furnace and could lift 250 times their own weight during the recovery process. The distribution of stationary and reversible phases was regulated by controlling the length ratio of the rigid and flexible segments. The AFM results showed that the distribution of the high- and low-modulus areas was successfully controlled, indicating the precise manipulation of stationary and reversible phases. In this process, for the very first time, the relationship between the shape memory properties and the distribution of stationary and reversible phases were managed to uncover. Furthermore, pioneering studies on energy absorption and release in shape memory cycles were conducted. This study may provide significant guidelines for future work on shape memory block copolymer aerogels.