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Oxygen plasma treatment of polydimethylsiloxane (PDMS) induces an ultrathin polyorganosilica (POSi) layer (< 10 nm) on top of a PDMS membrane, leading to excellent H2/gas separation properties and providing a rapid and scalable way to fabricate robust silica membranes compared with conventional high-temperature and time-consuming sol-gel methods. Here, we thoroughly investigate POSi membranes derived from poly(dimethylsiloxane-co-methylhydroxidesiloxane) (poly(DMS-co-MHOS)) containing -SiOH groups that can be more easily converted to silica networks than the -SiCH3 in PDMS. The effect of the polysiloxane structure and plasma treatment conditions (including plasma generating powers, oxygen flowrate, chamber pressure, and treatment time) on the silica chemistry, structure, and H2/CO2 separation properties are systematically determined to derive structure/property relationships. An optimized membrane exhibits H2 permeance of 880 GPU and H2/CO2 selectivity of 67 at 150 ℃, superior to state-of-the-art polymeric membranes. The membrane retains H2/CO2 selectivity as high as 46 when challenged with simulated syngas containing 2.8 mol% water vapor at 150 ℃, demonstrating the potential of these POSi membranes for practical applications. 

Over the last two decades, polymers with superior H₂/CO₂separation properties at 100–300 °C have gathered significant interest for H₂purification and CO₂capture. This timely review presents various strategies adopted to molecularly engineer polymers for this application. We first elucidate the Robeson's upper bound at elevated temperatures for H₂/CO₂separation and the advantages of high‐temperature operation (such as improved solubility selectivity and absence of CO₂plasticization), compared with conventional membrane gas separations at ~35 °C. Second, we describe commercially relevant membranes for the separation and highlight materials with free volumes tuned to discriminate H₂and CO₂, including functional polymers (such as polybenzimidazole) and engineered polymers by cross‐linking, blending, thermal treatment, thermal rearrangement, and carbonization. Third, we succinctly discuss mixed matrix materials containing size‐sieving or H₂‐sorptive nanofillers with attractive H₂/CO₂separation properties.

 

Despite decades of research, metallic corrosion remains a long‐standing challenge in many engineering applications. Specifically, designing a material that can resist corrosion both in abiotic as well as biotic environments remains elusive. Here a lightweight sulfur–selenium (S–Se) alloy is designed with high stiffness and ductility that can serve as an excellent corrosion‐resistant coating with protection efficiency of ≈99.9% for steel in a wide range of diverse environments. S–Se coated mild steel shows a corrosion rate that is 6–7 orders of magnitude lower than bare metal in abiotic (simulated seawater and sodium sulfate solution) and biotic (sulfate‐reducing bacterial medium) environments. The coating is strongly adhesive, mechanically robust, and demonstrates excellent damage/deformation recovery properties, which provide the added advantage of significantly reducing the probability of a defect being generated and sustained in the coating, thus improving its longevity. The high corrosion resistance of the alloy is attributed in diverse environments to its semicrystalline, nonporous, antimicrobial, and viscoelastic nature with superior mechanical performance, enabling it to successfully block a variety of diffusing species.