Porous polyimides from polycyclic aromatic linkers: selective Co₂ capture and hydrogen storage

Abstract

Porous polyimides are important class of macromolecules owing to their excellent redox behaviour, efficient capture of CO₂ and H₂ gases, interesting photocatalytic properties and superior thermal and chemical stabilities. Here we describe in detail, the synthesis and gas storage properties of a series of porous polyimides (Tr-NPI, Tr-PPI, Tr-CPI, Td-PPI and Td-CPI) with various network topologies derived from polycyclic aromatic hydrocarbon linkers. These polyimides are synthesized in a single step by the condensation of corresponding polycyclic aromatic dianhydrides (NDA, PDA and CDA) with structure directing amine (TAPA and TAPM) monomers, having trigonal and tetrahedral geometry. The structure of all the polymers was fully characterized by various techniques. The present work also introduces for the first time porous polyimides containing rigid polycyclic aromatic compounds such as coronene. All the polyimides presented here exhibit high thermal stability and show selectivity towards CO₂ uptake at room temperature (293 K), due to the presence of aromatic clouds and CO₂ phillic oxygen and nitrogen functionalities on their pore surface. Moreover these polymers also showed significant uptake of H₂ gas (77 K). The present work has significant implications on the design of robust porous organic solids from small molecules for efficient capture of CO₂ and H₂ gases.