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Using intermolecular interactions to crosslink PIM-1 and modify its gas sorption properties
- McDonald, Tom O., Akhtar, Riaz, Lau, Cher Hon, Ratvijitvech, Thanchanok, Cheng, Ge, Clowes, Rob, Adams, Dave J., Hasell, Tom, Cooper, Andrew I.
- Journal of materials chemistry A 2015 v.3 no.9 pp. 4855-4864
- absorption, carbon dioxide, chemical interactions, crosslinking, mixing, modulus of elasticity, nitrogen, permeability, polycyclic aromatic hydrocarbons, polymers
- The intermolecular interactions between the “polymer of intrinsic microporosity” PIM-1 and polycyclic aromatic hydrocarbons (PAHs) have been investigated with the aim of modifying the gas sorption and physical properties. Mixing PIM-1 with selected PAHs resulted in rapid precipitation of polymer. Blending PIM-1 with pyrene had a significant effect of the gas sorption properties of the resulting films; dramatically reduced N₂ uptake (77 K), whilst CO₂ uptake at 298 K was only slightly reduced. A gate-opening behaviour was also observed for the N₂ gas sorption (77 K), which was related to the pyrene content of the blend. Using an electron-donating PAH as the additive resulted in a stronger interaction. By exploiting a post-modification strategy after PIM-1 film formation, the absorption of either pyrene or 1-aminopyrene produced films with higher elastic moduli and greatly improved CO₂/N₂ gas sorption selectivities (293 K). Single gas permeability measurements revealed that while the 1-aminopyrene modified film possessed reduced CO₂ permeability, it possessed enhanced CO₂/N₂ selectivity. Importantly, the ageing of the permeability was halted over the 50 days tested, likely due to the physical crosslinking of the polymer chains by 1-aminopyrene.