| 초록 |
We report the significance of controlling the effective pore size in our newly developed hybrid CMS matrix for enhanced N2/CH4 selectivity based on experimental characterizations and density functional theory (DFT) calculations. A new class of CMS membranes with an excellent N2/CH4 selectivity is demonstrated by pyrolysis of a homogeneous, hydrogen-bonded blend of a polyimide and ladder-structured polysilsesquioxane. DFT calculations suggest that electron accumulation at SiOx phases of hybrid CMS membranes strongly hinders the diffusion of CH4 compared to N2 due to a larger electron overlap, resulting in a smaller effective pore size. Moreover, elevating the pyrolysis temperatures enhanced the N2/CH4 solubility selectivity due to the strong repulsive interaction between newly formed ultramicropores with CH4. As a result, the hybrid CMS membranes showed an excellent single gas and N2/CH4/C2H6 (20/76/4) mixed gas N2/CH4 selectivity (28 and 16, respectively). |
