Superior Nanoporous Polyimides via Supercritical CO2 Drying of Jungle‐Gym‐Type Polyimide Gels

Abstract We report novel nanoporous polyimides formed from jungle‐gym‐type rigid polyimide gels by supercritical CO 2 drying. By virtue of supercritical CO 2 drying to avoid the collapse of nanostructure, porosity above 90 vol.‐% was achieved. We found a rich variety of nanoporous structures in the range of 50–800 nm such as crisp fragments, minute network, and highly‐connected beads. These characteristic structures were formed by the competitive progress of liquid‐liquid phase separation and crystallization induced due to the two chemical reactions of end‐crosslinking and thermal imidization during gelation. magnified image