Development of excellent water-repellent coatings for metallic and ceramic surfaces

One of the most fascinating properties of various in sects and plant surfaces in nature is their water-repellent (superhydrophobicity) capability. The nature offers new insights to learn and replicate the same in designing artificial superhydrophobic structures for a wide range of applications such as micro-fluidics, micro-electronics, textiles, self-cleaning surfaces, anti-corrosion, anti-fingerprint, oil/water separation, etc. In general, artificial superhydrophobic surfaces are synthesized by creating roughness and then treating the surface with low surface energy materials. In this work, various super-hydrophobic coatings on metallic surfaces (aluminum, steel, copper, steel mesh) were synthesized by chemical etching process using different etchants and fatty acid. Also, SiO2nano/micro-particles imbedded polyethylene, polystyrene, and poly(methyl methacrylate) superhydrophobic coatings were synthesized on glass substrates. To know the applications of the coatings, surface morphology, contact angle, self-cleaning, anti-icing, anti-fogging, corrosion-resistance, and water-repellent characteristics were investigated at various conditions. Furthermore, durability of coatings was also studied by performing thermal, ultra-violet, and mechanical stability tests. The surface morphology confirms the creation of rough microstructures by chemical etching or by embedding particles and the contact angle measurements reveals the superhydrophobic nature. Experimentally it is found that the coatings have excellent self-cleaning, anti-corrosion, anti-fogging, anti-icing, and water-repellent nature. These coatings also withstand mechanical disturbances such surface bending, adhesive peeling, and abrasion. Coatings are also found to be thermal and ultra-violet stable. Additionally, metallic coatings are also reproducible. Hence aforesaid durable superhydrophobic surfaces have many potential industrial applications.