Super‐Water‐Repellent Al ₂ O ₃ Coating Films with High Transparency

Abstract

We have prepared transparent, super‐water‐repellent coating films of alumina on glass plates by a combination of geometric and chemical approaches. The contact angle for water in the films was 165° and the transmittance for visible light was higher than 92%. A roughness of 20 to 50 nm was obtained, which is too small to scatter visible light, while the degree of roughness was great enough to enhance the water‐repellent properties together with the chemical effect of a fluorine‐containing agent and gave a super‐water‐repellent surface. The coatings have great potential for practical applications such as eyeglasses, cover glasses for solar cells, windshields of automobiles, and so on.