Raja Swaidan

Ultra-Microporous Triptycene-based Polyimide Membranes for High-Performance Gas Separation

This Communication describes the synthesis and exceptional gas transport properties of two robust, solution-processable ultra-microporous (<7 Å) PIM-polyimides – KAUST-PI-1 and KAUST-PI-2 – integrating a three-dimensional 9,10-diisopropyltriptycene contortion center into a rigid fused-ring dianhydride. Rotation about the imide bonds is restricted by ortho-substituted methyl groups in the diamine. Bridgehead substitution at the 9,10-positions compounds the benefi ts of triptycene on three fronts: [ 13 ] First, it offers tunability of the porous texture; second, the triptycene imparts rigidity to short bridgehead substituents, effectively enhancing the overall three-dimensionality and rigidity of the moiety; third, it bolsters solution-processability by enhancing solubility. Functionalizing the bridgeheads with short branched isopropyl chains [ 18 ] primes the microstructure for highly permeable and highly selective diffusion-dominated performance surpassing all known polymers in industrial gas separations [ 5 ] including hydrogen (H 2 /N 2 , H 2 /CH 4 ) and oxygen (O 2 /N 2 ) separations, which constitute ∼75% of the gas separation market. [ 19 ]

The liquid phase epitaxy approach for the successful construction of ultra-thin and defect-free ZIF-8 membranes: pure and mixed gas transport study

The liquid-phase epitaxy (LPE) method was effectively implemented to deliberately grow/construct ultrathin (0.5-1 μm) continuous and defect-free ZIF-8 membranes. Permeation properties of different gas pair systems (O2-N2, H2-CO2, CO2-CH4, C3H6-C3H8, CH4-n-C4H10) were studied using the time lag technique.

Quest for Anionic MOF Membranes: Continuous sod-ZMOF Membrane with CO2 Adsorption-Driven Selectivity

We report the fabrication of the first continuous zeolite-like metal-organic framework (ZMOF) thin-film membrane. A pure phase sod-ZMOF, sodalite topology, membrane was grown and supported on a porous alumina substrate using a solvothermal crystallization method. The absence of pinhole defects in the film was confirmed and supported by the occurrence of quantifiable time-lags, for all studied gases, during constant volume/variable pressure permeation tests. For both pure and mixed gas feeds, the sod-ZMOF-1 membrane exhibits favorable permeation selectivity toward carbon dioxide over relevant industrial gases such as H2, N2, and CH4, and it is mainly governed by favorable CO2 adsorption.

Energy‐Efficient Hydrogen Separation by AB‐Type Ladder‐Polymer Molecular Sieves

Increases in hydrogen selectivity of more than 100% compared with the most selective ladder polymer of intrinsic microporosity (PIM) reported to date are achieved with self-polymerized A-B-type ladder monomers comprising rigid and three-dimensional 9,10-dialkyl-substituted triptycene moieties. The selectivities match those of materials commercially employed in hydrogen separation, but the gas permeabilities are 150-fold higher. This new polymer molecular sieve is also the most selective PIM for air separation.