Construction of amphiphilic networks in blend membranes for CO2 separation

Blend membranes have attracted great attention because they can combine the advantages of different polymers. To investigate the effect of amphiphilic polymer on the separation performance of blend membranes, a series of blend membranes were designed and fabricated by blending an amphiphilic polymer of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) into poly(ether-block-amide) (Pebax) polymer for CO2 separation. For the as-prepared Pebax/PEDOT:PSS blend membranes, the interconnected CO2-philic networks were constructed by hydrophilic anionic chains of PSS− for accelerating CO2 transport. Meanwhile, non-CO2-philic networks were constructed by the hydrophobic cationic chains of PEDOT+, which distributed around the PSS− chains to provide low friction diffusion for CO2. Therefore, the amphiphilic polymer of PEDOT:PSS was an excellent material for improving CO2 separation performance of blend membranes. The results showed that the Pebax/PEDOT:PSS blend membranes were endowed with excellent CO2 separation performance. Pebax/PEDOT:PSS blend membrane demonstrated the optimal separation performance with a CO2 permeability of 440.2±3.3 Barrer and a CO2/CH4 separation factor of 28±0.6. This study indicates that introducing the amphiphilic polymer into the blend membranes is an efficient strategy for gas separation.