Scalable superhydrophobic T-shape micro/nano structured inorganic alumina coatings

T-shape structure can make inorganic materials superhydrophobic, but conventional preparation methods based on etching is usually costly and unscalable. In this work, a facile and scalable technique utilizing plasma electrolytic oxidation (PEO) is employed to prepare superhydrophobic inorganic alumina coatings. By optimizing the gradient electric field, the etching behavior of OH– is tunable so that a T-shape micro/nano structured alumina coating can be prepared in one step. Without any organic modification, the coating shows a water contact angle (CA) of 150°±3° and water rolling angle (RA) of 8°±2°. The prepared inorganic ceramic coating remains superhydrophobicity under a harsh environment including 360 days of sunlight, and they have excellent corrosion resistance and can bear long-time flame burning. The preparation technique is simple and economical thereby boding well for great potentials in applications of solar cells, electronic devices, etc.