# US 2019/0169460 A1 · Hydrophobic coatings that include nanoparticles

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- Number: US 2019/0169460 A1
- Document ID: US20190169460A1
- Status: Published application
- Kind: A1
- Application number: 15/833,672
- Filed: 2017-12-06
- Published: 2019-06-06
- Earliest claimed: 2017-12-06
- Inventors: Eric Loth; Ilker Bayer; K Ghokulla Krishnan
- Web page: https://patentgrep.com/patent/US20190169460A1

## CPC

- C09D 133/16: Homopolymers or copolymers of esters containing halogen atoms
- B05D 1/12: Applying particulate materials (B05D1/06, B05D1/10 take precedence)
- B05D 3/12: by mechanical means
- B05D 5/083: {involving the use of fluoropolymers}
- B05D 7/56: {Three layers or more}
- B05D 7/584: {at least some layers being let to dry, at least partially, before applying the next layer (B05D7/587 takes precedence)}
- B64C 1/00: Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
- C09D 1/00: Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
- C09D 5/1681: {Antifouling coatings characterised by surface structure, e.g. for roughness effect giving superhydrophobic coatings or Lotus effect}
- C09D 5/1693: {as part of a multilayer system}
- F01D 5/00: Blades; Blade-carrying members (nozzle boxes F01D9/02); Heating, heat-insulating, cooling or antivibration means on the blades or the members {(special arrangements in rotors dealing with breaking off of part thereof F01D21/045)}
- F01D 5/288: {Protective coatings for blades}
- B05D 2490/50: compositions varying with a gradient perpendicular to the surface
- B64F 5/00: Designing, manufacturing, assembling, cleaning, maintaining or repairing aircraft, not otherwise provided for; Handling, transporting, testing or inspecting aircraft components, not otherwise provided for
- F03D 1/0675: {of the blades}
- F05B 2230/90: Coating; Surface treatment
- F05D 2300/211: Silica
- F05D 2300/43: Synthetic polymers, e.g. plastics; Rubber
- F05D 2300/512: Hydrophobic, i.e. being or having non-wettable properties
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- 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)
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- B64C: AEROPLANES; HELICOPTERS
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B64F: GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
- F03D: WIND MOTORS
- F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A coating and related methods useful for reducing insect residue on moving surfaces, such as turbine blades or aircraft. The coating can include alternating layers of a perfluorinated acrylic copolymer and silicon dioxide nanoparticles that have been infused into one another via thermal annealing processes. The coating may be super-hydrophobic and exhibits desirable durability characteristics.

## Claims

### Claim 1

A coating on a substrate, wherein the coating comprises:
a first layer that includes a perfluorinated acrylic copolymer;
a second layer that includes silicon dioxide nanoparticles and wherein the second layer is disposed adjacent to the first layer,
wherein the first layer and the second layer are partially infused into one another.

### Claim 2 (depends on 1)

The coating of claim 1, wherein the coating is a super-hydrophobic coating.

### Claim 3 (depends on 1)

The coating of claim 1, wherein the perfluorinated acrylic copolymer is a hydrophobic PMC.

### Claim 4 (depends on 1)

The coating of claim 1, wherein the first layer is between 8 and 10 microns thick.

### Claim 5 (depends on 1)

The coating of claim 1, wherein the second layer is 300 nanometers or less thick.

### Claim 6 (depends on 1)

The coating of claim 1, wherein the first layer is disposed between the substrate and the second layer.

### Claim 7 (depends on 1)

The coating of claim 1, wherein the coating further comprises
a third layer that includes a perfluorinated acrylic copolymer and wherein the third layer is disposed adjacent to the second layer; and
a fourth layer that includes silicon dioxide nanoparticles and wherein the fourth layer is disposed adjacent to the third layer.

### Claim 8 (depends on 7)

The coating of claim 7, wherein the coating further comprises
a fifth layer that includes a perfluorinated acrylic copolymer and wherein the fifth layer is disposed adjacent to the fourth layer;
a sixth layer that includes silicon dioxide nanoparticles and wherein the sixth layer is disposed adjacent to the fifth layer;
a seventh layer that includes a perfluorinated acrylic copolymer and wherein the seventh layer is disposed adjacent to the sixth layer; and
an eighth layer that includes silicon dioxide nanoparticles and wherein the eighth layer is disposed adjacent to the seventh layer,
wherein each of the first, second, third, fourth, fifth, sixth, sevenths, and eighth layers are partially infused into at least one adjacent layer.

### Claim 9

A method of coating a substrate, wherein the method comprises:
forming a first layer over the substrate, wherein forming the first layer includes spraying a first solution that includes perfluorinated acrylic copolymer dissolved in a first solvent;
forming a second layer over the substrate, wherein forming the second layer includes spraying a second solution onto a surface of the first layer, wherein the second solution includes silicon dioxide nanoparticles and a second solvent; and
heating the substrate, wherein heating the substrate results in the second layer partially infusing into the first layer, thereby forming the coating on the substrate.

### Claim 10 (depends on 9)

The method of claim 9, wherein the first solvent is acetone, THF, or MEK.

### Claim 11 (depends on 9)

The method of claim 9, wherein the perfluorinated acrylic copolymer is present in the first solution in an amount that is between 15 and 30 percent by weight of the first solution.

### Claim 12 (depends on 9)

The method of claim 9, wherein the second solvent is acetone, THF, MEK, or chloroform.

### Claim 13 (depends on 9)

The method of claim 9, wherein the method further comprises
forming a third layer over the substrate, wherein forming the third layer includes spraying a third solution onto a surface of the second layer, wherein the third solution includes perfluorinated acrylic copolymer dissolved in a third solvent; and
forming a fourth layer over the substrate, wherein forming the fourth layer includes spraying a fourth solution onto a surface of the third layer, wherein the fourth solution includes silicon dioxide nanoparticles and a fourth solvent.

### Claim 14 (depends on 13)

The method of claim 13, wherein the method further comprises,
forming a fifth layer over the substrate, wherein forming the fifth layer includes spraying a fifth solution onto a surface of the fourth layer, wherein the fifth solution includes perfluorinated acrylic copolymer dissolved in a fifth solvent;
forming a sixth layer over the substrate, wherein forming the sixth layer includes spraying a sixth solution onto a surface of the fifth layer, wherein the sixth solution includes silicon dioxide nanoparticles and a sixth solvent;
forming a seventh layer over the substrate, wherein forming the seventh layer includes spraying a seventh solution onto a surface of the sixth layer, wherein the seventh solution includes perfluorinated acrylic copolymer dissolved in a seventh solvent; and
forming an eighth layer over the substrate, wherein forming the eighth layer includes spraying an eighth solution onto a surface of the seventh layer, wherein the eighth solution includes silicon dioxide nanoparticles and an eighth solvent.

### Claim 15 (depends on 14)

The method of claim 14, wherein the method further includes heating the substrate at least once after spraying one or more of third, fourth, fifth, sixth, seventh, and eighth solutions to partially infuse each of the third, fourth, fifth, sixth, seventh, or eighth layers into at least one adjacent layer.

### Claim 16 (depends on 9)

The method of claim 9, wherein the coating has a total thickness of between 30 and 50 microns.

### Claim 17 (depends on 9)

The method of claim 9, wherein the method further comprises removing non-stick portions of the second layer after the substrate has been heated.

### Claim 18 (depends on 17)

The method of claim 17, wherein removing non-stick portions of the second layer includes removing non-stick portions with a pressure dust gun.

### Claim 19 (depends on 1)

A method of reducing insect residue on a surface, the method comprising, consisting of, or consisting essentially of
disposing a coating according to claim 1 over the surface, and allowing insects to impinge on the surface.

### Claim 20 (depends on 19)

The method of claim 19, wherein the surface is a surface on a turbine or an aircraft.