The research team led by Professor Haiqing Lin from the University of Buffalo has reported a membrane that challenges long-standing assumptions in gas-separation design. Their work, focuses on crosslinked polyamines, a class of polymers typically used because of their strong attraction to carbon dioxide. That attraction is usually considered helpful in encouraging the target gas to move through a membrane more easily. In this case, however, experiments and simulations showed that the interaction between the polymer and carbon dioxide is so strong that it slows the gas down instead of assisting its passage.
Hu, L., Gottipalli, A. J., Zhang, G., Fung, K., Tran, T., Esmaeili, N., Zhang, P., Ding, Y., Shi, K., & Lin, H. (2025). Sabatier principle in designing CO 2 -philic but blocking membranes. Science Advances, 11(47). https://doi.org/10.1126/sciadv.adz2830
This unexpected behaviour prompted the researchers to shift their perspective. If the membrane traps carbon dioxide so effectively, it may perform well in situations where hydrogen must pass while carbon dioxide is blocked. Hydrogen and carbon dioxide commonly appear together in industrial gas streams, so an efficient method of separating them is central to hydrogen purification and many energy-related processes. Additional tests supported the idea: the membrane allowed hydrogen to move through it roughly 1,800 times more easily than carbon dioxide. Prior polymer membranes offered selectivity closer to one hundred, so the reported value sets a new benchmark for this type of material.
Professor Haiqing Lin from the University of Buffalo stated,
“It’s very counterintuitive, and it challenges traditional thinking in gas separation science.”
The membrane’s performance is notable not just for its selectivity but also for its practicality. The researchers showed that the crosslinked polyamines can be manufactured into thin-film composite structures suitable for industrial membrane modules. The material also demonstrated a degree of self-healing and remained stable when exposed to harsh operating conditions. These factors make the membrane more than a laboratory curiosity and place it within reach of potential large-scale use.
Industrial gas separations, particularly those involving hydrogen and carbon dioxide, consume a sizeable amount of energy. Processes such as cryogenic distillation or pressure-swing adsorption remain the dominant commercial options, but they carry both energy and cost burdens. Membranes with higher selectivity and strong durability may contribute to lowering those burdens. If materials like the one reported by Lin’s team can be produced in large quantities with consistent performance, they could reduce energy use and emissions associated with hydrogen purification.
The work also highlights an emerging design principle. Conventional thinking suggests that membranes should be engineered to attract the gas they are intended to transport. The University at Buffalo study demonstrates that strong attraction can backfire, creating a bottleneck rather than an advantage. By exploiting this effect, the researchers turned an apparent flaw into a functional benefit, using the material’s affinity for carbon dioxide to exclude it while letting hydrogen permeate. This counterintuitive approach may influence how future membranes are designed, shifting attention toward binding strength, diffusion limits and how these factors interact under real operating conditions.
Whether this membrane becomes a commercial product will depend on further engineering studies. Long-term stability, resistance to fouling, performance under pressure swings and compatibility with existing hydrogen production systems will require evaluation. The broader economic picture, including material cost, manufacturing scalability and overall energy savings, will also shape its industrial prospects. Even so, the reported selectivity suggests that polymer membranes can perform at a level previously considered difficult to achieve without more specialised materials. It opens the possibility that other polymers designed for one purpose may show unanticipated advantages when their molecular interactions are reconsidered.
For hydrogen-related industries, the findings present an interesting opportunity. Cleaner hydrogen production depends not only on the method of generating hydrogen but also on how efficiently it can be separated from other gases. If membranes like this one continue to demonstrate strong performance, they may become part of a more energy-efficient route to producing low-carbon hydrogen.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
