Wettability of ceramic surfaces -A wide range control of surface wettability from super hydrophilicity to super hydrophobicity, from static wettability to dynamic wettability

Surface wettability is dependent to surface energy of the material. Therefore the surface wettability basically reflects its intrinsic surface property and it has been thought that it is hard to be controlled arbitrarily. For example, inorganic materials such like metal oxides usually exhibit relatively hydrophilic property as compared with organic materials. However recent series of studies by our group revealed that photo-induced surface reaction, nanometer scale roughness, nanometer scale physical and chemical heterogeneity affect wettability greatly. This fact clearly shows that the surface wettability of a metal oxide can be controlled from superhydrophilic state to superhydrophobic state. The target of control includes not only static wettability but also dynamic wetttability. Oxide surface with high dynamic hydrophobicity can be obtained by optimizing these factors. Water repellency of developed hydrophobic ceramic surface turned out to be like a polymer surface. The novel technology to control wettability of ceramic surfaces is expected to contribute to various applications.