Electrostatic-modulated interfacial crosslinking and waterborne emulsion coating toward waterproof, breathable, and antifouling fibrous membranes

Developing hydrophobic surfaces for flexible fibrous membranes has attracted tremendous attention for their potential applications in waterproofing, antifouling, and drag reduction. However, conventional methods, such as hydrothermal, coating, and phase separation, often involve complex preparation processes, plugging of porous structures, and heavy use of organic solvents. Herein, a facile and eco-friendly assembly strategy is proposed for fabricating superior hydrophobic surfaces on fibrous membranes. Firstly, a hierarchical rough structure was created on the fiber surface using titanium dioxide nanoparticles as building blocks by a one-pot procedure based on electrostatic complexation and interfacial crosslinking. The procedure is performed in aqueous media, at low temperature (50℃) and very fast (∼20 min). Subsequently, a waterborne emulsion was developed by low-surface-energy organosilicon self-assembly in aqueous media, which was adopted to coat fiber substrate for surface hydrophobization. The amount of organosilicon is reduced by >90 % of that required in the traditional coating. Consequently, the resultant fibrous membranes exhibit a robust hydrophobic surface with UV-resistant, wash durability, photocatalytic self-cleaning effect, and excellent breathable properties. Besides, this general waterborne hydrophobic coating strategy could be applied to various hydrophilic substrates, including fabrics, aerogels, and sponges. This work provides a novel method to design and fabricate multi-functional hydrophobic surfaces.