. 2018 Oct 18;3(10):13510–13523. doi: 10.1021/acsomega.8b01364

cm³ cmHg, Diffusivity Selectivity (α_D), and Solubility Selectivity (α_S) Values of the Polyimides^a^,^b.

	CO₂		O₂		N₂		CH₄		CO₂/CH₄		O₂/N₂
polymer	D	S	D	S	D	S	D	S	α_D	α_S	α_D	α_S
PI A	20.2	8.7	21.7	2.8	6.5	1.5	3.10	1.10	6.51	7.90	3.33	1.86
PI B	17.4	6.5	21.0	2.7	5.9	1.5	2.54	0.98	6.85	6.63	3.55	1.80
PI C	15.5	6.3	16.1	2.5	4.8	1.4	2.20	0.90	7.04	7.00	3.35	1.78
PI D	15.2	6.2	15.6	2.2	5.0	1.2	2.17	0.89	7.00	6.96	3.12	1.83

D is the gas diffusion coefficients in 10^–8 cm²/s.

S is the gas solubility coefficients in 10^–2 cm³ (STP)/cm³ cmHg (S = P/D).

Table 4. Gas Diffusion Coefficients, D (108 cm2/s), Solubility Coefficients (S) in 10–2 cm3 (STP)/cm3 cmHg, Diffusivity Selectivity (αD), and Solubility Selectivity (αS) Values of the Polyimidesa,b.