# US 10,478,802 B2 · Anti-fingerprint photocatalytic nanostructure for transparent surfaces

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- Number: US 10,478,802 B2
- Document ID: US10478802B2
- Status: Granted
- Kind: B2
- Application number: 14/274,642
- Filed: 2014-05-09
- Published: 2014-11-13
- Granted: 2019-11-19
- Earliest claimed: 2013-05-09
- Assignees: Massachusetts Institute of Technology
- Applicants: Robert E. Cohen; Michael F. Rubner; Gareth H. McKinley; George Barbastathis; Hyungryul Johnny Choi; Kyu Chul Park; Hyo Min Lee
- Inventors: Robert E. Cohen; Michael F. Rubner; Gareth H. McKinley; George Barbastathis; Hyungryul Johnny Choi; Kyu Chul Park; Hyo Min Lee
- Web page: https://patentgrep.com/patent/US10478802B2

## CPC

- B01J 21/063: {Titanium; Oxides or hydroxides thereof}
- B01J 35/39: Photocatalytic properties
- B01J 35/45: Nanoparticles
- B01J 37/0217: {Pretreatment of the substrate before coating}
- B01J 37/0219: {the coating containing organic compounds}
- B01J 37/0244: {Coatings comprising several layers}
- C03C 17/007: {containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase}
- C03C 17/34: with at least two coatings having different compositions (C03C17/44 takes precedence)
- C09D 1/00: Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
- C09D 5/00: Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced {(electrically insulating plastics, resins or waxes H01B3/30)}; Filling pastes
- C09D 5/006: {Anti-reflective coatings}
- C09D 5/14: Paints containing biocides, e.g. fungicides, insecticides or pesticides (C09D5/16 takes precedence)
- C09D 7/48: Stabilisers against degradation by oxygen, light or heat
- B01J 37/349: {making use of flames, plasmas or lasers}
- B01J 2231/70: Oxidation reactions, e.g. epoxidation, (di)hydroxylation, dehydrogenation and analogues
- C03C 2217/42: consisting of particles only
- C03C 2217/425: consisting of a porous layer
- C03C 2217/477: Titanium oxide
- C03C 2217/71: Photocatalytic coatings
- C03C 2217/734: comprising an alternation of high and low refractive indexes
- C03C 2217/75: Hydrophilic and oleophilic coatings
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)

## Abstract

Titania-based porous nanoparticle coatings are mechanically robust, with low haze, which exhibit short time scales for decomposition of fingerprint oils under ultraviolet light. The mechanism by which a typical dactylogram is consumed combines wicking of the sebum into the nanoporous titania structure followed by photocatalytic degradation. These TiO2 nanostructured surfaces are also anti-fogging, anti-bacterial, and compatible with flexible glass substrates and remain photocatalytically active in natural sunlight.

## Claims

### Claim 1

A structure comprising:
a transparent substrate; and
a multi-layer optically transmissive nanoparticle structure residing on the substrate comprising an outermost layer of titanium dioxide nanoparticles wherein the outermost layer of titanium dioxide nanoparticles of the multi-layer structure is superhydrophilic and oleophilic, and alternating layers of low and high index of refraction materials below the outermost layer to provide broadband anti-reflectivity
wherein the alternating layers of low and high index of refraction materials form a nanoporous coating and have a smaller refractive index than the substrate and
the optically transmissive nanoparticle structure capable of wicking sebum into the nanoporous coating of the nanoparticle structure followed by photocatalytic degradation.

### Claim 2 (depends on 1)

The structure of claim 1, wherein the outermost layer of titanium dioxide nanoparticle is porous.

### Claim 3 (depends on 1)

The structure of claim 1, wherein the multi-layer structure comprises material selected from the group consisting of silicon dioxide, titanium dioxide, silicon, metallic glass, polymer, metal, or combinations thereof to provide a selected functionality.

### Claim 4 (depends on 3)

The structure of claim 3, wherein the selected functionality is anti-reflectivity, anti-fogging, anti-scratch, or anti-bacterial.

### Claim 5 (depends on 1)

The structure of claim 1, wherein the substrate is flexible.

### Claim 6 (depends on 1)

The structure of claim 1, wherein the nanoparticle size and thickness of the multi-layer structure are selected to maximize a photocatalytic effect and to minimize light scattering.

### Claim 7 (depends on 1)

The structure of claim 1, wherein an oil deposition on the outermost layer of titanium dioxide nanoparticles of the structure is degraded after exposure to sunlight.

### Claim 8 (depends on 7)

The structure of claim 7, wherein the oil deposition is degraded within 3 hours of exposure to sunlight.

### Claim 9 (depends on 1)

The structure of claim 1, wherein an oil deposition on the outer most layer of titanium dioxide nanoparticles of the structure is degraded after exposure to UV light.

### Claim 10 (depends on 9)

The structure of claim 9, wherein the oil deposition is degraded within 3 hours of exposure to sunlight.

### Claim 11 (depends on 1)

The structure of claim 1, wherein the size of the titanium dioxide nanoparticles is less than 1 nm.