Photocatalytically hydrophilifying and hydrophobifying material

摘要

A method for highly hydrophilifying the surface of an article by photoexcitation of a semiconductor photocatalyst and maintaining the hydrophilicity is disclosed. A layer containing a photocatalyst is formed on a substrate. Onto the surface of the layer are fixed a hydroxyl group upon photoexcitation of the photocatalyst and a physically adsorbed water molecule in the vicinity of the hydroxyl group upon photoexcitation of the photocatalyst. Thus, the surface is highly hydrophilified. Further, this surface, simultaneously with the hydrophilification, exhibits higher hydrophobicity.