Preparation of ultra-stable ZIF-8 dispersions in water and ethanol

In the fabrication of zeolitic imidazolate frameworks (ZIFs) thin films and membranes, the preparation of stable ZIFs dispersions is crucial. Herein, ultra-stable ZIF-8 aqueous dispersions were obtained successfully for the first time. It was found that, after the synthesis of ZIF-8, with the increased washing times, the positive surface potentials of ZIF-8 particles decrease, resulting in increased aggregate size. The ZIF-8 dispersions washed for zero times are very stable in water, and there is no settlement even after centrifuging at 8000 rpm for 6 min. The aggregate size of ZIF-8 dispersions in ethanol aqueous solutions decreases with increased ethanol content, and there is no apparent settlement in absolute ethanol even after 13 days. The ultra-stable ZIF-8 dispersions display great potentials in fabrication of thin films and membranes.