Preparation of polyimide aerogel beads using phase separation techniques and supercritical drying

Kurzfassung

This study presents the preparation of polyimide (PI) aerogel beads based on the exposure of PI polymer solutions to a liquid non-solvent via the non-solvent induced phase separation method (NIPS). To fine tune the morphology and thus properties of the PI aerogels, such as the specific surface area, the PI solutions in either DMF or NMP were primed with various levels of an additional antisolvent, such as water, prior to dripping the PI solutions into a non-solvent coagulation bath containing anhydrous ethanol leading to the formation of polymer PI beads. The PI beads were then solvent exchanged and washed with ethanol and dried by either supercritical drying or atmospheric pressure oven drying. The Specific Surface Area (SSA) and Scanning Electron Microscope (SEM) images were generated and compared.

This study demonstrates that priming the PI solution and selecting the drying method are useful tuning knobs for fabricating PI aerogel beads with a wide range of morphologies and different surface areas.