# US 8,784,713 B2 · Method of making articles with super-hydrophobic and/or self-cleaning surfaces

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- Number: US 8,784,713 B2
- Document ID: US8784713B2
- Status: Granted
- Kind: B2
- Application number: 13/906,900
- Filed: 2013-05-31
- Published: 2013-10-03
- Granted: 2014-07-22
- Earliest claimed: 2010-05-24
- Assignees: Integran Technologies Inc.
- Applicants: Integran Technologies Inc.
- Inventors: Jared J. Victor; Uwe Erb; Klaus Tomantschger; Nandakumar Nagarajan; Diana Facchini; Mioara Neacsu
- Web page: https://patentgrep.com/patent/US8784713B2

## CPC

- B29C 59/02: by mechanical means, e.g. pressing {(B29C59/007 takes precedence; embossing expanded porous articles B29C44/5627)}
- B29C 37/0053: {Moulding articles characterised by the shape of the surface, e.g. ribs, high polish (mould construction therefor B29C33/42; surface shaping of articles B29C59/00; by incorporating filler in or near the surface B29C70/64)}
- B29C 43/021: {characterised by the shape of the surface}
- B29C 59/022: {characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor}
- B29C 2043/025: {forming a microstructure, i.e. fine patterning}
- B29C 2059/023: {Microembossing}
- Y10T 428/139: Open-ended, self-supporting conduit, cylinder, or tube-type article
- Y10T 428/24355: Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Super-hydrophobic and self-cleaning articles produced by imprinting exposed surfaces with suitable fine-grained and/or amorphous metallic embossing dies to transfer a dual surface structure, including ultra-fine features less than or equal to 100 nm embedded in and overlaying a surface topography with macro-surface structures greater than or equal to 1 micron are disclosed.

## Claims

### Claim 1

A method for manufacturing an article formed of a polymeric material and having at least one of a hydrophobic and a self-cleaning outer surface, the method for manufacturing comprising the steps of:
(i) providing an embossing die having an exposed surface portion formed of a metallic material, the metallic material having at least one of a fine-grained microstructure with an average grain size between 2 and 5,000 nm and an amorphous microstructure, a smooth surface of the metallic material being inherently hydrophilic at room temperature, the smooth surface has a surface roughness less than or equal to 0.25 microns;
(ii) incorporating surface structures into the exposed surface portion of the embossing die to define a textured surface portion of the embossing die, said textured surface portion rendering the inherently hydrophilic smooth surface of the metallic material at room temperature hydrophobic; and
(iii) imprinting at least a portion of the outer surface of the polymeric material of the article directly with the textured surface portion of the embossing die.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the imprinting step increases the contact angle for water at room temperature of the outer surface portion of the polymeric material to at least 125° and/or decreases the tilt angle for water at room temperature of said outer surface portion of the polymeric material to less than or equal to 25°.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the metallic material has a fine-grained microstructure.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the metallic material has an amorphous microstructure.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the metallic material is a multi-layer laminate.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the metallic material is free standing or applied as a coating to at least a portion of a substrate.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the fine-grained and/or amorphous microstructure of the metallic material is made by a process selected from electroless deposition, electrodeposition, physical vapor deposition, chemical vapor deposition, cold spraying and gas condensation.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the outer surface portion of the article comprises randomly distributed surface structures containing a plurality of micron-sized features, wherein the plurality of micron-sized features further has a substructure comprising of a plurality of nanoscale features.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the exposed metallic material surface portion is treated by at least one process selected from the group consisting of chemical etching, electrochemical etching, plasma etching, shot-peening, grinding, and machining.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the exposed metallic material surface portion is treated by shot-peening followed by etching.

### Claim 11 (depends on 1)

The method according to claim 1, wherein said metallic material is selected from the group of:
(i) one or more metals selected from the group consisting of Ag, Al, Au, Co, Cr, Cu, Fe, Ni, Mo, Pd, Pt, Rh, Ru, Sn, Ti W, Zn and Zr,
(ii) pure metals or alloys containing at least two of the metals listed in (i), further containing at least one element selected from the group of B, C, H, O, P and S;
(iii) any of (i) or (ii) where said metallic coating also contains particulate additions in the volume fraction between 0 and 95% by volume.

### Claim 12 (depends on 11)

The method according to claim 11, wherein the metallic material contains particulate addition of at least 1% by volume and said particulate addition is of one or more materials selected from the group consisting of a metal, a metal oxide, a carbide, a polymer material, ceramic, glass and a carbon selected from the group consisting of carbon nanotubes, diamond, graphite, and graphite fibers.

### Claim 13 (depends on 1)

The method according to claim 1, further comprising incorporating dual-roughness surface structures into the exposed metallic material surface portion of the embossing die.

### Claim 14 (depends on 13)

The method according to claim 13, wherein the dual-roughness surface structures comprise a primary surface structure and a secondary surface structure at least partially overlaying said primary surface structure, the primary surface structure including surface features having dimensions and a spacing between adjacent primary surface features in the range of 1 micron to 1,000 microns, and the secondary surface structure including surface features having dimensions and a spacing between adjacent secondary surface features in the range of 1 nm to less than or equal to 100 nm.

### Claim 15 (depends on 1)

The method according to claim 1, wherein said embossing die comprises at least one metallic material selected from the group consisting of Ni, Co, P, Cu and Fe.

### Claim 16 (depends on 1)

The method according to claim 1, wherein said polymeric material comprises a material selected from the group consisting of unfilled or filled epoxies, phenolic or melamine resins, polyester resins, urea resins, thermoplastic polymers, polyamides, mineral filled polyamide resin composites, polyphthalamides, polyphtalates, polystyrene, polysulfone, polyimides, neoprenes, polybutadienes, polyisoprenes, butadiene-styrene copolymers, poly-ether-ether-ketone (PEEK), polycarbonates, polyesters, liquid crystal polymers, polycarbonates, acrylonitrile-butadiene-styrene (ABS), chlorinated polymers, and fluorinated polymers.

### Claim 17

A method for manufacturing an article formed of a polymeric material and having at least one of a hydrophobic and a self-cleaning outer surface, the method for manufacturing comprising the steps of:
(i) providing an embossing die formed of a metallic material, the metallic material having at least one of a microstructure which is fine-grained with an average grain size between 2 and 5,000 nm and an amorphous microstructure;
(ii) incorporating surface structures into at least an exposed metallic material surface portion of the embossing die to define a textured surface portion by first shot-peening the metallic material surface and followed by etching the metallic material surface, the textured surface portion rendering the at room temperature inherently hydrophilic surface of the smooth surface portion of the metallic material surface having a surface roughness (Ra) less than or equal to 0.25 microns at room temperature hydrophobic; and
(iii) imprinting at least a portion of an outer surface of the polymeric material of the article directly with the textured metallic material surface portion of the embossing die.

### Claim 18 (depends on 17)

The method according to claim 17, wherein the imprinting step increases the contact angle for water at room temperature of said outer surface portion of the polymeric material to at least 125° and/or decreases the tilt angle for water at room temperature of said outer surface portion of the polymeric material to less than or equal to 25°.

### Claim 19 (depends on 17)

The method according to claim 17, further comprising incorporating dual-roughness surface structures into the exposed metallic material surface portion of the embossing die, wherein the dual-roughness surface structures comprise primary surface structures and secondary surface structures at least partially overlaying said primary surface structures, and a linear population of said primary surface structures is in the range of 5 to 1000 per mm.

### Claim 20 (depends on 17)

The method according to claim 17, wherein the metallic material has a fine-grained microstructure.

### Claim 21 (depends on 17)

The method according to claim 17, wherein the metallic material has an amorphous microstructure.

### Claim 22 (depends on 17)

The method according to claim 17, wherein the metallic material is a multi-layer laminate.

### Claim 23 (depends on 17)

The method according to claim 17, wherein the metallic material is free standing or applied as a coating to at least a portion of a substrate.