In-situ generation of hydrated nanoparticles on commercial stainless steel mesh for durable superhydrophilicity and self-cleaning

The superhydrophilic membranes always face the problem of easy loss of water favoring property due to the easy adsorption of organic contaminants in air during storage. Here we present a material with durable superhydrophilicity and self-cleaning property through fluorination of commercial stainless steel mesh, and demonstrate the positive effect of crystal water on the maintainment of superhydrophilicity. Different from most reported superhydrophilic materials, fluorinated stainless steel mesh (F-mesh) can hydrate water in the form of crystal water and nanoparticles can be in-situ generated onto F-mesh wall upon hydration action. The crystal water can protect the surface from being contaminated by organic contaminants in air and is beneficial to the maintainment of superhydrophilicity up to at least 229 days. The long-lasting superhydrophilicity promote F-mesh to be applied in recyclable oil/water separation to solve the serious pollution caused by oily wastewater. The strong hydratability also endows fluorinated stainless steel plate with self-cleaning property even when they are already wetted by oil. The idea of crystal water may offer a general guideline for other superhydrophilic materials to keep superhydrophilicity and F-mesh shows great potential in the fields of biology and environment.