Figure 3.

(a) CH₄ and (b) CO₂ pure-gas sorption isotherms at 35 °C vs. gas fugacity. Blue squares were obtained with 6FDA-mPDA films in our custom-built barometric system. Blue diamonds were obtained with 6FDA-mPDA films via gravimetric sorption. CO₂ pure-gas gravimetric sorption was also performed with a 6FDA-mPDA powder sample (blue stars). Sorption isotherms for polydimethylsiloxane (PDMS) [11], polysulfone (PSF) [45], polycarbonate (PC) [42,46], 6FDA-6FpDA polyimide [44], poly [1-trimethylsilyl-1-propyne] (PTMSP) [15], and polymers of intrinsic microporosity (PIM)-1 [20] are also shown. Interpolations were performed via the dual-mode sorption (DMS) model [42]—DMS parameters were determined in-house. PDMS uptakes were interpolated linearly.