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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. 

This study details the enhancement of CO2 selectivity in ring opening metathesis polymerization (ROMP) polymers that contain nitrile moieties and micro-pore generating ladder side chains. A material, CN-ROMP homopolymer, with nitriles in the ladder side chains was originally targeted and synthesized, however its low molecular weight and backbone rigidity precluded film formation. As a result, an alternative method was pursued wherein copolymers were synthesized using norbornene (N) and nitrile norbornene (NN). Herein, we report an investigation of the structure–property relationships of backbone functionalization and grafting density on the CO2 transport properties in these ROMP polymers. Nitrile-containing copolymers showed an increase in CO2/CH4 sorption selectivity and a concomitant increase in CO2/CH4 permselectivity when compared to the unfunctionalized (nitrile free) analogs. The stability in CO2 rich environments is enhanced as grafting density of the rigid, pore-generating side chains increases and an apparent tunability of CO2 plasticization pressure was observed as a function of norbornene content. Lower loadings of norbornene resulted in higher plasticization pressure points. Gas permeability in the ROMP copolymers was found to correlate most strongly with the concentration of ladder macromonomers in the polymer chain. 

This review provides a comprehensive overview on the effects of plasticization on microporous polymer membranes, as well as strategies to mitigate this phenomenon for gas separation applications. 

Augmented Reality (AR) glasses separate dyadic interactions on diferent sides of the lens, where the person wearing the glasses (primary user) sees an AR world overlaid on their partner (secondary actor). The secondary actor interacts with the primary user under- standing they are seeing both physical and virtual worlds. We use grounded theory to study interaction tasks, participatory design ses- sions, and in-depth interviews of 10 participants and explore how AR real-time modifcations afect them. We observe a power imbalance attributed to the: (1) lack of transparency of the primary user’s view, (2) violation of agency over self-presentation, and (3) discreet record- ing capabilities of AR glasses. This information asymmetry leads to a negotiation of behaviors to reach a silently understood equilibrium. This paper addresses underlying design issues that contribute to power imbalances in dyadic interactions and ofers nuanced insights into the dynamics between primary users and secondary actors.