LAUSR

To examine the potential of ion gels as materials for CO 2 separation membranes, inorganic/organic double-network ion gel (DN ion gel) membranes with different ionic liquid (IL) contents were fabricated. The composition of the inorganic and organic networks was optimized to maximize the mechanical strength of the DN ion gel. The DN ion gel with an inorganic/organic network composition of 0.35 mol/mol showed the maximum mechanical strength because the inorganic and organic networks sufficiently acted as sacrificial bonds and hidden lengths, respectively. Using DN ion gel membranes with different IL contents prepared with the optimized precursor solution, the relationship between the CO 2 permeability and IL content of the DN ion gel membranes was examined. The DN ion gel membrane with 95.2 wt% IL had a CO 2 permeability of 1380 barrer, which was ~67% of the theoretical maximum predicted for the pure IL membrane. The CO 2 permeability of the DN ion gel membrane exponentially increased with increasing IL content and approached the theoretical maximum. DN ion gels with high strength can be used to develop maximum-performance IL-based CO 2 separation membranes by giving the membrane the maximum IL potential. The effect of the ionic liquid content in tough inorganic/organic double-network (DN) ion gel membrane on the CO 2 permeability was investigated. By optimizing the composition of the inorganic and organic networks, the mechanical strength of the DN ion gel was significantly increased, and the DN ion gel membrane with more than 95 wt% of an ionic liquid was successfully prepared. With the increase in the ionic liquid content, the CO 2 permeability of the DN ion gel membrane exponentially increased up to ~67% of the theoretical maximum CO 2 permeability.