Fabrication of Superhydrophobic Aluminum Surfaces Using Sink Electric Discharge Machining

The evolution of surfaces with superhydrophobic properties has attracted significant attention due to their potential for reducing the transmission of infections caused by pathogens in sterile environments. The antibacterial and anti-biofouling properties of the resulting aluminum surface, which has the potential for use in hygiene-critical environments such as hospitals and public transport hubs. While chemical etching and passivation with low surface energy octyltriethoxysilane (OTES) molecules have been used to fabricate such surfaces, they come with significant environmental and health risks. In this study, the use of electrical discharge machining (EDM) as a single-step manufacturing process for the fabrication of durable, metallic hydrophobic surfaces are explored. Using a hydrocarbon dielectric, the simple sink EDM can swiftly develop inherently water-repellent surfaces with contact angles reaching to 142.4° (close to 150°). This approach offers a more sustainable and efficient alternative to traditional fabrication methods while providing a tunable superhydrophobic surface with anti-biofouling and antibacterial properties.