A Durable Fluorine-Free MOF-Based Self-Cleaning Superhydrophobic Cotton Fabric for Oil-Water Separation

It is challenging to fabricate durable and fluorine-free superhydrophobic surfaces through simple procedures. In this study, a novel fabrication method for constructing robust, wearable, and fluorine-free superhydrophobic surfaces on cotton textiles has been achieved via in situ growth of zeolitic imidazolate framework-8 (ZIF-8) layers followed by polydimethylsiloxane (PDMS) modification. The roughness created by the sheet-like structure is optimized by tuning the mole ratio between 2-methylimidazole and zinc nitrate during the in situ growth, while polydopamine (PDA) is introduced to improve the durability and stability. The resultant PDA/ZIF-8/PDMS@cotton fabric exhibits a maximum water contact angle of 156.4 degrees and a low sliding hysteresis angle of 3.8 degrees. The as-prepared superhydrophobic fabric also presents excellent durability and stability, and outstanding resistance against continuous sunlight exposure and various chemical reagents. In addition, the superhydrophobic surface possesses excellent self-cleaning and anti-fouling performance, as well as high separation efficiency >97% and reusability when serving as a filter during the oil-water separation. The proposed approach and prepared superhydrophobic fabric strongly demonstrate the potential applications in oil-water separation with a prolonged life cycle.