Multifunctional Superhydrophobic Surface for Oil‐Water Separation, Anti‐Icing, and Anti‐Corrosion via a Highly Stable Waterborne Superhydrophobic Emulsion

Abstract Waterborne superhydrophobic emulsions are of great significance in terms of the safety and sustainability of their production and application. Limited by the fact that hydrophobic polymers are susceptible to agglomeration and settling, it is still challenging to fabricate stable waterborne superhydrophobic emulsions. Here, an oil‐in‐water type Pickering emulsion is exploited to stabilize the oil‐water surface using nanoparticles as the emulsifier. The prepared Pickering oil droplets are cured into microspheres via an in‐situ pre‐cross‐linking process, thereby forming stable waterborne superhydrophobic emulsions. The cured microspheres and nanoparticle emulsifiers immobilized on the microspheres’ surface endow the resulting surface with abundant micro‐ and nanostructures, acquiring an ultrahigh contact angle of 171°, and an ultralow rolling angle of 1°. The resulting surface imparts superhydrophobicity and mechanical and chemical durability, enabling the oil‐water separation, anti‐icing, and anti‐corrosion applications. Moreover, the waterborne superhydrophobic emulsions remain highly stable for nine months. This work presents a scalable, cost‐effective, and eco‐friendly approach for the design of waterborne superhydrophobic emulsions, opening up a new prospect for the practical application of waterborne superhydrophobic emulsions.