High performance membranes containing rigid contortion units prepared by interfacial polymerization for CO2 separation

Polymeric membranes have been widely researched for several decades due to their good processability and low cost. Herein, high-performance thin-film composite (TFC) membranes were prepared by interfacial polymerization using N-methyldiethanolamine (MEDA), 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethylspirobisindane (TTSBI) and trimesoylchloride (TMC). The effects of segmental chain motion on the gas separation performance of the TFC membranes were investigated for the polymeric membranes featuring rigid and contorted sites along the polymer backbone by inducting TTSBI. The results suggested that the introduction of rigid and contorted structures improved the cavities in the membrane, impeded the transport of larger gas, and enhanced the diffusive selectivity. Therefore, the TFC membrane exhibited high permeance and high selectivity with CO2 permeance of about 1800 GPU and CO2/N-2 selectivity of 370 at 0.11 MPa, which is a remarkable improvement in gas separation performance.