A green one-step fabrication of superhydrophobic metallic surfaces of aluminum and zinc

Superhydrophobic surfaces on metal materials play a significant role in considerable industries because of its eminent water-repel and anti-pollutant ability. A facile green methodology is proposed to in situ fabricate superhydrophobic surface on aluminum surface by simply immersing the plate in an aqueous mixture solution of HCl and stearic acid. Sample possesses high contact angle (150°) and low roll-off angle (8°), because the surface simultaneously combines rough structure with low surface energy. SEM images and contact angle measurements directly show the rough structures and contact angles. It did not require any toxic chemical agents, sophisticated techniques or equipments. The surface modification and ligand bonding of stearic acid on aluminum surface were characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. More importantly, the obtained superhydrophobic surfaces show remarkable stability in acidic and alkaline conditions, and the contact angle can stay above 150° without apparent fluctuation for water droplet with pH value ranging from 1 to 14. A prominent enhancement on the corrosion resistance capacity of the aluminum and zinc plates was achieved after the superhydrophobic treatment.