ZIF-8@Poly(ionic liquid)-Grafted Cotton Cloth for Switchable Water/Oil Emulsion Separation

It is highly challenging to separate stabilized water/oil emulsions with sizes below 20 μm. Here, we propose a simple and scalable process via the in situ grafting of ZIF-8 nanoparticles and a poly­(ionic liquid) (PIL) onto a commercial cotton cloth (CC) fabric. Switchable wettability between superhydrophilicity/underwater superoleophobicity and superhydrophobicity/superoleophilicity was easily realized via the anion exchange of the PIL. ZIF-8 nanoparticles effectively improved the superhydrophilicity and superolelphilicity of ZIF-8@PIL-grafted cotton cloth (CC-ZIF-PIL), while also performing the dual functions of the separation of oil-in-water (O/W) and water-in-oil (W/O) emulsions. Accordingly, effective water/oil emulsion separation with a high efficiency (η > 99%), selectivity, stability, and durability was obtained using the CC-ZIF-PIL. These features indicate that CC-ZIF-PIL has promising application in switchable water/oil emulsion separation devices.