Water/oil repellent layer-provided article and method for producing it

An article, comprising:

• a substrate,
• a water/oil repellent layer comprising a hydrolyzed condensate of a fluorinated compound having a hydrolyzed silyl group, and
• a silicon oxide layer comprising alkali metal atoms, present between the substrate and the water/oil repellent layer,
• wherein the silicon oxide layer has a surface in contact with the water/oil repellent layer,
• wherein in the silicon oxide layer, an average concentration of the alkali metal atoms in a region with a depth from the surface in contact with the water/oil repellent layer of from 0.1 to 0.3 nm, is from 2.7×1019 atoms/cm3 to 8.2×1021 atoms/cm3, and
• wherein the fluorinated compound is a compound having the hydrolyzed silyl group and a poly(oxyperfluoroalkylene) chain.