Polyimide (PI) aerogels with excellent mechanical and thermal stability, low density, and flexibility have attracted extensive attention in recent years. However, the existing preparation method usually requires chemical pre-crosslinking followed by supercritical drying or freeze drying, and then thermal imidization, which has the weakness of a complicated preparation method and high cost. In this study, PI aerogels were prepared by a simple method that involved freeze extraction and chemical imidization, which exhibited low density (0.14 g cm(-3)), high porosity (85.61), excellent thermal stability (T-5 and T-g were 418.12 and 230.60 degrees C, respectively), shape fidelity, and compressibility. Furthermore, this method regulated the pore size, such as the macro/microstructure, and then used the PI aerogel ink to build complex architectures by 3D printing. As a proof of concept, pyramids, multilayer grids, ring-hole disks, Chinese knots and cuboids were printed, and all of them exhibited the shape fidelity property after freeze-extraction and chemical imidization. Therefore, we believe this novel preparation method enables significant promotion of the application potential of PI aerogels and 3D printing.
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