PROBLEM TO BE SOLVED: To satisfy all other characteristics obtained as surface characteristics of a material by a method wherein the surface of the material is irradiated with an electron to control wettability to water keeping a surface crystal lattice state of the material surface.
SOLUTION: The surface of a material is irradiated with an electron in vacuum. As the material to be used, not only alkali halides such as NaF, LiF, etc., if only a mutual action of the surface can be varied with irradiation of the electron, such material may be applicable. An irradiation amount of electron irradiation, through an energy depends upon the material kind, is preferable 1 to 2 pieces per nm, and the irradiation energy is preferably 30e V or under. Then, wettability to water is controlled while keeping a surface crystal lattice state of the material surface. Since the wettability can be controlled thereby after optimizing surface characteristics other than the wettability, development or the like of a surface coating capable of satisfying all other characteristics which can be obtained as the surface characteristics of the material is made possible.