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

Abstract

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 degrees +/- 3 degrees and water rolling angle (RA) of 8 degrees +/- 2 degrees. 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.