A facile method to fabricate the polyimide aerogels with controllable microstructure by freeze-drying

A facile method for preparing porous polyimide aerogels was successfully developed. Poly (amic acid) solution composed by 2,2-bis(3,4-anhydrodicarboxyphenyl) hexafluoropropane and 4,4′-oxydianiline were synthesized in solvent dioxane or dioxane/t-butanol. The poly (amic acid) aerogels can be easily fabricated by freeze-drying for removing the solvent in poly (amic acid) solution, and polyimide aerogels with controllable microstructure were obtained through thermal imidization. This method was used in preparing polyimide aerogels without chemical imidization and solvent exchange process in the pretreatment process. The as-prepared polyimide aerogels show unique microstructure, low density, excellent mechanical properties, and superhydrophobicity.