Method for photocatalytically rendering a surface of a substrate superhydrophilic, a substrate with superhydrophilic photocatalytic surface, and method of making thereof

A method of manufacturing a composite with a hydrophilifiable surface, comprising the steps of:

• providing a substrate having a surface;
• and,
• coating the surface of said substrate with a photoreactive layer comprising a photocatalyst, wherein said photocatalyst operates after photoexcitation thereof to render the than about 20.degree. in terms of the contact angle with water.

A coating composition for use in forming a photocatalytically hydrophilifiable coating on a surface, said coating composition comprising a photocatalyst operable after photoexcitation thereof to render the surface of said coating hydrophilic on the order of less than about 20.degree. in term of the contact angle with water.

A method for rendering the surface of a substrate hydrophilic, comprising the steps of:

• providing a substrate coated with a photocatalytic layer comprising a photocatalyst;
• and,
• subjecting said photocatalyst to photoexcitation to thereby render the surface of said layer hydrophilic, wherein the surface of said layer presents a water wettability of less than about 20 .degree. in terms of the contact angle with water.

A method for preventing adherent moisture condensate or water droplets from growing on a surface, said method comprising the steps of:

• providing a substrate coated with a photocatalytic layer comprising a photocatalyst;
• and
• subjecting said photocatalyst to photoexcitation to thereby render the surface of said layer hydrophilic, wherein the surface of said lay presents a water wettability of less than about 20.degree. in terms of the contact angle with water, and whereby adherent moisture condensate and water droplets are caused to spread over the surface of said layer.

A method for rendering bydrophilic a surface of a substrate in need of hydrophilification, comprising the steps of:

• providing a substrate coated with a photocatalytic layer comprising a photocatalyst;
• and
• subjecting said photocatalyst to photoexcitation to thereby render the surface of said photocatalytic layer hydrophilic, wherein the surface of said layer presents a water wettability of legs than about 20.degree. in terms of the contact angle with water.

A composite with a hydrophilifiable surface, comprising;

• a substrate having a surface;
• and
• a photocatalytic layer comprising a photocatalyst, said layer being bonded to the surface of the substrate, wherein the surface of said layer is further coated with a protective layer that does not interfere with the hydrophilifiability of the photocatalytic layer.

A composite with a hydrophilifiable surface, comprising:

• a substrate having a surface;
• and
• a photocatalytic layer comprising a photocatalyst, said layer being bonded to the surface of the substrate, wherein said substrate includes alkaline metal ions or alkaline-earth metal ions, and wherein a thin film for preventing said ions from diffusing from said substrate into said photocatalytic layer is interleaved between said substrate and said photocatalytic layer.