During membrane-based gas separation, a gas mixture is typically driven through a membrane by pressure where separation is achieved through differences in individual gas permeabilities . The performance of membrane processes is determined by the membrane's permeability for a specific gas species, Pi, where i specifies the gas type. The membrane permeability is calculated from Fick's law of diffusion, |𝐽 | 𝑃 Δ𝑝/𝑙 , where Ji is the flux of gas i, and Δ𝑝 is the pressure drop across a membrane of thickness l. When comparing the permeability of gas A with that of gas B, another performance measure is the membrane's selectivity between two gases, α, which is defined as 𝛼 𝑃 /𝑃 . An ideal membrane for a given binary gas separation would have high permeability and high selectivity. Increasing gas permeability and selectivity in these membranes would allow for more efficient industrial processes by increasing the process throughput, reducing energy costs, and achieving a purer product . However, there is a well-known permeability-selectivity tradeoff for polymer gas-separation membranes , which is defined by the Robeson upper bound CO2/CH4 and CO2/N2 separations ) that reflect improved membrane performance. Identifying new materials that break this upper bound has driven and continues to drive materials discovery efforts for membranes .