A Drop‐and‐Drain Method for Convenient and Efficient Fabrication of MOF/Fiber Composites

Abstract The fabrication of flexible composites by integrating metal–organic frameworks (MOFs) with flexible substrates is a critical strategy for developing advanced materials with excellent feasibility and processability. These flexible MOF‐based composites play a particularly important role in the separation and purification processes. However, several drawbacks remain challenge to overcome such as long processing time, high‐cost, complicated processes, or harsh reaction conditions. In this paper, a convenient and efficient method is reported for fabricating MOF/fiber composites using a simple drop‐and‐drain (D&D) process. By exploiting the electrostatic interactions between the positively charged MOF particles and negatively charged fiber‐based flexible substrates, a uniform coating of MOF on flexible fibers are achieved. This is accomplished by allowing the MOF ink to drop and drain through a substrate using a custom‐made Teflon cell. Additionally, the D&D method enables the production of multiple layers of composites in a single‐step process. UiO‐66 and ZIF‐8 submicroparticles and various substrates such as cotton‐pad, cotton‐fabric, nylon‐fabric, PET‐fabric, and filter‐paper are employed to create flexible MOF/fiber composites. These composites demonstrate outstanding capacities for capturing negatively charged organic dyes, including methyl orange and indigo carmine. Furthermore, the MOF/fiber composites can be reused for dye capture after a simple washing process.