Carbon molecular sieve (CMS) membranes have been developed to replace or support energy-intensive cryogenic distillation for olefin/paraffin separation. Olefin and paraffin have similar molecular properties, but can be separated effectively by a CMS membrane with a rigid, slit-like pore structure. A variety of polymer precursors can give rise to different outcomes in terms of the structure and performance of CMS membranes. Herein, for olefin/paraffin separation, the CMS membranes derived from a number of polymer precursors (such as polyimides, phenolic resin, and polymers of intrinsic microporosity, PIM) are introduced, and olefin/paraffin separation properties of those membranes are summarized. The effects from incorporation of inorganic materials into polymer precursors and from a pyrolysis process on the properties of CMS membranes are also reviewed. Finally, the prospects and future directions of CMS membranes for olefin/paraffin separation and aging issues are discussed.

For ethylene/ethane separation, a CMS (carbon molecular sieve) membrane was developed with a PAN (polyacrylonitrile) polymer precursor on an alumina support. To provide an excellent thermal property to PAN precursor prior to the pyrolysis, the stabilization as a pre-treatment process was carried out. Tuning the stabilization condition was very important to successfully preparing the CMS membrane derived from the PAN precursor. The stabilization and pyrolysis processes for the PAN precursor were finely tuned, and optimized in terms of stabilization temperature and time, as well as pyrolysis temperature, heating rate, and soaking time. The PAN stabilized at >250 °C showed improved thermal stability and carbon yield. The CMS membrane derived from stabilized PAN showed reasonable separation performance for ethylene permeance (0.71 GPU) and ethylene/ethane selectivity (7.62), respectively. Increasing the pyrolysis temperature and soaking time gave rise to an increase in the gas permeance, and a reduction in the membrane selectivity. This trend was opposite to that for the CMS membranes derived from other polymer precursors. The optimized separation performance (ethylene permeance of 2.97 GPU and ethylene/ethane selectivity of 7.25) could be achieved at the pyrolysis temperature of 650 °C with a soaking time of 1 h. The separation performance of the CMS membrane derived from the PAN precursor was comparable to that of other polymer precursors, and surpassed them regarding the upper bound trade off.

Flexible neural probes with integrated recording, optical stimulation, and drug delivery capabilities offer unprecedented access to neural circuit dynamics. However, their long-term utility is compromised by foreign body responses that isolate recording sites from target neurons. This study introduces photoinitiated chemical vapor deposition (piCVD) as a transformative approach to neural interface stability through ultrathin (<100 nm) anti-fouling coatings. Unlike conventional hydrogel coatings that impair electrical signal transmission, our piCVD-applied poly(2-hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) coating maintains electrical functionality by preserving low impedance while providing superior anti-fouling properties. In vitro protein adsorption studies demonstrated near-complete resistance to both albumin and fibrinogen compared to uncoated surfaces, with the coating maintaining stability even after 24 h of sonication-durability unachievable with conventional wet-chemistry methods. When evaluated in mouse models over three months, the coated probe maintained high-quality spontaneous neural recordings and optically evoked potentials throughout the study period, with signal-to-noise ratios improving from 18.0 at week 1-20.7 at week 13. This performance significantly correlates with 66.6 % reduction in glial scarring, 84.6 % increase in neuronal preservation compared to uncoated probes. The specific combination of CVD methodology and optimized copolymer composition achieves long-term stability, representing a significant advance over the typical one-month limitation of conventional coatings. These results establish piCVD antifouling coatings as an enabling technology for chronic neural interfaces in both basic neuroscience research and emerging neuroprosthetic applications.