Build up ‘highway’ in membrane via solvothermal annealing for high-efficient CO2 capture

Poly (ethylene oxide) (PEO) membranes are attractive for CO 2 capture due to the particular dipolar–quadrupolar interaction between EO units and CO 2 molecules, which offer high CO 2 /N 2 selectivity. However, the low CO 2 permeability of PEO membranes hampers their practical applications. Herein, a simple solvothermal annealing approach was proposed to enhance the flexibility of PEO chains via ‘activating’ the disengagement and rearrangement of side chains, which is essential for boosting the gas permeability . The effects of solvothermal annealing temperature, time, and solvent on the CO 2 /N 2 separation performance were comprehensively investigated. The mechanism for the performance enhancement was proposed: a “highway” for gas transportation was built up by the released flexible side chains, which were confirmed by the mechanical and Li ion conductivity characterizations. The optimized PEO membrane offers a superior CO 2 permeability of 1294 Barrer, a high CO 2 /N 2 selectivity of 50, and 110-h long-term running stability, being beyond the 2008 Robeson’s upper bound line and promoting the practical application of PEO membranes in CO 2 capture by reducing the cost.