Ultra–light, elastic, magnetic Polyimide/Fe3O4 composite aerogel with magnetic actuation function

Introducing magnetic property into aerogels will greatly expand their application opportunities. Herein, instead of triethylamine solution, a low-cost and little-toxicity aqueous ammonia is used as the basic solution of polyamide acid (PAA), and tert-butanol is used as the regulator to regulate the pore size of aerogel. Finally, an intelligent polyimide/Fe 3 O 4 (PI/Fe 3 O 4 ) aerogel is proposed via a unique combination of in-situ deposition and freeze–drying–thermal imidization. As-obtained PI/Fe 3 O 4 aerogel has a low density (0.041 − 0.087 g cm − 3 , depending on the doping amount of Fe 3 O 4 nanoparticles), a high thermal decomposition temperature (up to 550 °C, N 2 atmosphere), good mechanical properties (even under a compression ratio of 60%), certain recovery performance, and good bending flexibility. Additionally, the PI/Fe 3 O 4 aerogel also shows a saturation magnetization of 84.76 emu g − 3 , enabling it to generate magneto-induced shape memory under the action of small magnetic sheets. This work provides a new idea for the preparation of magnetic polyimide aerogel, and may inspire many application opportunities for polyimide aerogel, such as self-sensing flexible actuators, micro-nano switches, and micro-sensing.