Enhancing H2-permselectivity of high-flux hollow fiber membrane via in-situ layer-by-layer surface treatment
This manuscript presents the first application of a layer-by-layer (LbL) permselective all-polymer coating to a Torlon© polyamide imide (PAI) hollow fiber substrate to realize a new class of manufacturable, highly selective, composite polymer membrane for hydrogen separation from carbon dioxide and nitrogen light gases. Sub-micron, defect-free conformal coatings of [PEI10/PAA4] polymeric pair were successfully deposited on both PEI-functionalized and untreated hollow fiber substrates. Surface functionalization was found to provide twofold benefits of introducing a positively charged surface to aid LbL deposition while enhancing selective transport of hydrogen through the membrane achieving high selectivities of H2:CO2 (>200:1) and H2:N2 (>2000:1) at 40 Barrers of H2 permeability exceeding the Robeson upper bound for homogenous polymer films. The deposition of low-cost, water-based polymers and easy to fabricate LbL membranes on conventional hollow fiber has potential use at industrial scale for hydrogen separation.
N. K. Mishra, N. Patil, C. Long, S. Yi, D. Hopkinson, J. C. Grunlan, B. A. Wilhite, J. Membr. Sci., 2020, 615, 118312.