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 degrees C and 1 bar, the mixture separation factors of H-2/CO2, H-2/N-2, H-2/CH4, and H-2/C3H8 are 8.9, 16.2, 31.5 and 712.6, with H-2 permeances higher than 1.8 X 10(-7) mol.m(-2).s(-1).Pa-1, which is promising for hydrogen separation and purification.