Synthesis of perfectly alternating copolymers for polymers of intrinsic microporosity

Copolymer's properties are controlled not only by co-monomers' composition but also their sequence distribution along the chain. We hereby report a strategy to the synthesis of perfectly alternating PIMs copolymer, an important class of material for gas separation membrane. We achieve this copolymer microstructure through two-pot synthesis process via ABA trimer intermediate. For comparison, both alternating and statistical copolymers with same composition were prepared and characterized with H-1 and C-13 NMR, FT-IR, MALDI-ToF, GPC, TGA, DSC and WAXD. The present work offers new method for repeating unit sequence control in step growth polymerization system.