Bio-inspired polydopamine: A versatile and powerful platform for covalent synthesis of molecular sieve membranes

Inspired by the bioadhesive ability of the marine mussel, a simple, versatile, and powerful synthesis strategy was developed to prepare highly reproducible and permselective molecular sieve membranes by using polydopamine as a novel covalent linker. Attributing to the formation of strong covalent and noncovalent bonds, ZIF-8 nutrients are attracted and bound to the support surface, thus promoting the ZIF-8 nucleation and the growth of uniform, well intergrown, and phase-pure ZIF-8 molecular sieve membranes. The developed ZIF-8 membranes show high hydrogen selectivity and thermal stability. At 150 C and 1 bar, the mixture separation factors of H₂/CO₂, H ₂/N₂, H₂/CH₄, and H ₂/C₃H₈ are 8.9, 16.2, 31.5 and 712.6, with H₂ permeances higher than 1.8 × 10^-7 mol·m^-2·s^-1·Pa^-1, which is promising for hydrogen separation and purification.