Template-free synthesis of crystalline polyimide spheres with radiate branches

Abstract A new type of crystalline polyimide spheres with radiate branches (PI-1) and BET surface area up to 350 m 2  g − 1 has been synthesized by in-situ self-assembly of the polyimide macromolecules. The high surface area of this porous material is mainly stemmed from the mesopores formed by the oriented packing of nanowhiskers. The pore formation mechanism in this material is very different from any existing microporous polymers ever reported.