Natural gas production and utilization have grown tremendously in recent decades, which highlights the need for improved, high-throughput purification methods. In the field of polymeric membrane-based gas separations, a detailed understanding of molecular structure–property relationships are critical to overcoming the permeability–selectivity trade-off. Prior work has highlighted that alkoxysilyl-substituted vinyl-addition polynorbornenes (VAPNBs) are promising candidates for natural gas purification, having exceptional H2S/CH4 and modest CO2/CH4 permselectivity. To improve their CO2/CH4 separation performance, we herein describe a series of fluoroalkoxysilyl-substituted VAPNBs. We demonstrate that the incorporation of fluoroalkoxysilyl substituents yields a series of polymeric materials whose CO2/CH4 permselectivity increases as a function of fluorine incorporation. Interestingly, these enhanced selectivity characteristics are realized with minimal decreases to overall CO2 permeability. While it was initially hypothesized that introduction of fluorinated units would decrease CH4 solubility, detailed sorption analysis revealed that the observed increases in CO2/CH4 permselectivity were due almost exclusively to enhanced CO2 sorption in fluorine-containing VAPNBs. Computational studies provided insights into the electronic interaction energies between gas molecules and polymer repeat units across the nonfluorinated and fluorinated series, respectively.

The generation of radioactive waste has a prominent negative impact on the use of nuclear energy due to potential health concerns and cost of waste storage. This potential impact continues to rise as the quantity of waste increases due to the increasing growth in energy demand. One of the leading contributions to the radioactivity of this waste is due to the presence of actinides. The removal of these actinides by ligand-based solvent extraction methodologies provides an invaluable process necessary for the promotion of nuclear energy. By evaluating different ligands that are currently applied for actinide solvent extractions, more effective ligands could be proposed and synthesized for the successful separation of actinides from nuclear waste. Here, density functional theory (DFT) calculations for a variety of ligands and actinides are reported to explain the extraction process. Different solvation and ligation effects were evaluated for the computation of stability constants. The ratio of water and nitrate ligands in the coordination environment of actinides (Ac­(III), Th­(IV), Am­(III), and Cm­(III)) was first examined. Results from this step provided reliable initial conditions for the extraction of these actinides in both the aqueous (343HOPO) and the organic phase (BTBP). We also report a DFT benchmarking study as well as a modified BTBP ligand performance evaluation.