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Asymmetric hollow fibers were spun with either an internal or external skin layer for an emerging class of microporous polymers using a dry jet, wet quench extrusion technique. The poly(arylene ether) (PAE) used for spinning contains free volume promoting spirobifluorene (SBF) and tert-Bu-triptycene (TBTrip) units in the backbone, providing benefits to penetrant size sieving and solution processability in accessible solvents relevant for commercial-scale manufacturing. However, microporous polymers often suffer from poor spinnability, and relatively high amounts of volatile solvents such as tetrahydrofuran (THF) are required to promote external skin layer formation. Therefore, an alternate spinning technique was developed that required no volatile solvents and resulted in a defect-free internal skin layer for low-pressure applications. Dope solution compositions and ternary phase diagrams for the polymer, SBF-TBTrip-I, are also reported, along with details on fiber morphology. Regardless of the spinning technique used, the SBF-TBTrip-I fibers exhibited desirable gas transport properties with O2/N2 and CO2/CH4 selectivities comparable to those of dense films and H2-based selectivities occasionally surpassing those of dense films. By forming thin selective layers, permeances for all gases tested were significantly higher than those of comparable thick films. This work presents an early attempt to manufacture this emerging class of polymers into industrially relevant hollow fiber membrane geometries while providing useful insights into the unique challenges of spinning microporous polymers. 

Easily tunable and processable, porous organic polymers (POPs) have found increasing utility in various applications. Molecular modeling and simulations are invaluable tools in polymer science but remain under-reported in the POP literature. Accurate modeling and simulation of these materials could boost the discovery of high-performance POPs and allow for a more thorough contribution to big data. These polymers contain free volume-promoting structural units, such as iptycenes, and exhibit high glass-transition temperatures, excellent thermal stability, and tunable functionality. However, popular transferable force fields utilized in allatomistic molecular dynamics (MD) simulations are not fully parametrized for intrinsically porous thermoplastic materials. We present a streamlined workflow for all-atomistic MD simulations of nonporous and porous amorphous polymer materials. In conjunction with the programs ORCA, Q-Force, Assemble!, and GROMACS, a highly accessible methodology is established for force field (FF) parametrization, creation of initial configurations, and simulation of various nonporous and porous polymers. This protocol can reproduce experimental bulk densities and fractional free volume values for amorphous polymeric materials with excellent accuracy and has been made available as a Python package, called PolyPal. As an example, we present our results using PolyPal on a series of nonporous and porous polymers that were previously synthesized and experimentally characterized. FF accuracy was also validated through solid-state NMR studies. These simulations will not only open new avenues for the rational design of high-performance POPs through the contribution of improved insight but also provide a streamlined pathway for simulating previously unexplored porous polymeric materials. 

The design of flow reactors for heterogeneous photocatalysis is key to enhancing the control, efficiency, and scalability of chemical reactions. However, conventional designs such as slurry reactors and fixed bed reactors often suffer from poor light penetration, challenging catalyst attachment to the support, and difficult separations. We report an efficient and robust methodology for the functionalization of perfluoroalkoxy (PFA) coil reactors with different fluorinated photocatalysts [a perylene diimide (F-PDI) and poly(p-phenylene ethynylene) polymers (PPEST and POLPDI)] through fluorophilic interactions. We have evaluated the efficiency of photocatalyst-functionalized coil reactors in continuous flow experiments through the [2 + 2] photocycloaddition of 9-vinylcarbazole (VCZ) using blue and green light (440 and 525 nm). The conversion of VCZ to the product 1,2-trans-dicarbazylcyclobutane (t-DCZCB) was continuously monitored by in-line nuclear magnetic resonance (NMR) spectroscopy, and we found that PPEST was the most robust photocatalyst coating of those studied, leading to high conversions with different lamp powers and residence times. Further experiments proved that PPEST-functionalized coil reactors were stable and efficient after 18 h of continuous flow with conversions from around 50 to 75%. 

H₂S/CH₄and CO₂/CH₄separations show opposing trends, making simultaneous improvement challenging. This is addressed by increasing free volume to enhance competitive sorption effects and boosting diffusion selectivity throughin situcrosslinking. 

We report a scalable synthesis of high-molecularweight poly(arylene ether)s (PAEs) using decafluorobiphenyl under SNAr reaction conditions and the preparation of enantiopure (R,R)-6,11-di(tert-butyl)triptycene-1,4-hydroquinone. The nonfluorinated biphenyl-based PAE was also synthesized using Pdcatalyzed C−O coupling methods, and structure−property comparisons were made from the different biphenyl-based polymers. The integration of free-volume-promoting triptycene moieties on the main chain gives rise to intrinsic porosity, which can be further modulated by incorporating biphenyl or perfluorobiphenyl comonomers. The nonfluorinated PAE exhibited a BET surface area of 270 m2 g−1, whereas the racemic and enantiopure fluorinated PAEs showed higher BET surface areas of 454 and 368 m2 g−1, respectively. WAXS analysis revealed that all of the polymers tested have a greater disruption of chain packing compared to related polyimides, with the fluorinated PAEs having the highest average interchain spacing. The fluorinated PAEs also demonstrated high gas permeability as a result of their free volume. The triptycene-based PAEs also were resistant to plasticization even at CO2 pressures of ∼31 bar.