Method for photocatalytically rendering a surface of a substrate superhydrophilic, a substrate with superhydrophilic photocatalytic surface, and method of making thereof
First Claim
1. A composite with a hydrophiliflable surface, comprising:
- a substrate having a surface; and
a photocatalytic layer comprising a photocatalyst, said layer being bonded to the surface of said substrate wherein said photocatalyst operates after photoexcitation thereof to render the surface of said composite hydrophilic such that the surface presents, a water wettability of less than about 20°
in terms of the contact angle with water.
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Accused Products
Abstract
The surface of a substrate is coated with an abrasion-resistant photocatalytic coating comprised of a semiconductor photocatalyst. Upon irradiation by a light having a wavelength of an energy higher than the bandgap energy of the photocatalyst, water is chemisorbed onto the surface in the form of hydroxyl groups (OH--) whereby the surface of the photocatalytic coating is rendered highly hydrophilic. In certain embodiments, the surface of a mirror, lens, or windowpane is coated with the photocatalytic coating to exhibit a high degree of antifogging function. In another embodiment, an article or product coated with the photocatalytic coating is disposed outdoors and the highly hydrophilic surface thereof is self-cleaned as it is subjected to rainfall. In a still another embodiment, an article is coated with the photocatalytic coating and, when the article is soaked in, rinsed by or wetted with water, fatty dirt and contaminants are readily released without resort to a detergent.
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Citations
133 Claims
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1. A composite with a hydrophiliflable surface, comprising:
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a substrate having a surface; and a photocatalytic layer comprising a photocatalyst, said layer being bonded to the surface of said substrate wherein said photocatalyst operates after photoexcitation thereof to render the surface of said composite hydrophilic such that the surface presents, a water wettability of less than about 20°
in terms of the contact angle with water. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A method of manufacturing a composite with a hydrophilifiable surface, comprising the steps of:
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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°
in terms of the contact angle with water. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 77, 78, 79)
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73. 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°
- in term of the contact angle with water.
- View Dependent Claims (74, 75, 76, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90)
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91. A method for rendering the surface of a substrate hydrophilic, comprising the steps of:
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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 °
in terms of the contact angle with water. - View Dependent Claims (92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 111)
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108. A method for preventing adherent moisture condensate or water droplets from growing on a surface, said method comprising the steps of:
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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°
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. - View Dependent Claims (109, 110, 112, 113, 114, 115, 116, 117, 118)
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119. A method for cleaning a substrate, comprising the steps of:
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providing a substrate coated with a photocatalytic layer comprising a photocatalyst; 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°
in terms of the contact angle with water; and
,contacting said substrate with water, whereby deposits and contaminants adhering on the surface of said layer are washed away by water, and whereby contaminants in said water are prevented from adhering to said surface. - View Dependent Claims (120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130)
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131. A method for rendering bydrophilic a surface of a substrate in need of hydrophilification, comprising the steps of:
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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°
in terms of the contact angle with water.
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132. A composite with a hydrophilifiable surface, comprising;
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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.
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133. A composite with a hydrophilifiable surface, comprising:
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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.
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Specification