Anti-fingerprint coatings
An article having a nanostructured surface and a method of making the same are described. The article can include a substrate and a nanostructured layer bonded to the substrate. The nanostructured layer can include a plurality of spaced apart nanostructured features comprising a contiguous, protrusive material and the nanostructured features can be sufficiently small that the nanostructured layer is optically transparent. A continuous layer can be adhered to a plurality of surfaces of the nanostructured features to render the plurality of surfaces of the nanostructured features both hydrophobic and oleophobic with respect to fingerprint oil comprising eccrine secretions and sebaceous secretions, thereby providing an anti-fingerprinting characteristic to the article.
1. An article having a nanostructured surface layer, comprising:
a substrate; and
a nanostructured SiO 2 -rich layer bonded to said substrate, wherein said nanostructured layer comprises a plurality of spaced apart branched nanostructured spinodal features comprising a contiguous, protrusive material, wherein a width of said nanostructured features ranges from 1 to 500 nm;
a continuous hydrophobic layer adhered to a plurality of surfaces of the nanostructured features, wherein the continuous layer has a thickness of from 1 to 60 nm, wherein the continuous layer comprises a polyphobic compound, wherein the at least one polyphobic compound is both hydrophobic and oleophobic;
a plurality of interconnected nanopores formed by said plurality of nanostructured features, the nanopores having a major diameter ranging from 5-500 nm, the nanostructured layer having a thickness of no more than 2000 nm, and the interconnected nanopores extending through the thickness of the layer; and
an oil having a boiling point of at least 120° C. pinned in the plurality of nanopores by Van der Walls forces, such that the nanostructured features protrude from the oil, wherein the nanostructured surface layer is superoleophobic having a contact angle with a drop of fingerprint oil of from 70 to 180 degrees, superhydrophobic having a contact angle with water of at least 140 degrees, optically transparent having a Strehl ratio ≥0.5, antireflective and reflecting less than 1% of incident visible light and blocking at least 80% of UV radiation across a broad spectrum at of least 150 nm, and smear resistant.
2. The article according to claim 1 , wherein the continuous layer comprises a polyphobic compound, wherein the at least one polyphobic compound is both hydrophobic and oleophobic.
3. The article according to claim 2 , wherein the at least one polyphobic compound is at least one selected from the group consisting of poly[2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole-co-tetrafluoroethylene] and poly[2,2,4-trifluoro-5-trifluoromethoxy-1,3,-dioxole].
4. The article according to claim 1 , wherein the oil pinned in the plurality of nanopores formed by said plurality of nanostructured features is held in place by at least one selected from the group consisting of surface tension forces, van der Waal forces, and combinations thereof.
5. The article according to claim 1 , wherein a width, length and height of each of said plurality of spaced apart nanostructured features ranges from 1 to 500 nm.
6. The article according to claim 1 , wherein said nanostructured layer is atomically bonded to said substrate.
7. The article according to claim 1 , wherein said nanostructured layer is chemically bonded directly to said substrate.
8. The article according to claim 1 , wherein said plurality of spaced apart nanostructured features provide an anti-reflective surface.
9. The article according to claim 1 , wherein the continuous layer has a thickness of from 31 to 60 nm.