SUPERHYDROPHOBIC AND SUPEROLEOPHOBIC NANOSURFACES

• US 20140011013A1
• Filed: 12/20/2011
• Published: 01/09/2014
• Est. Priority Date: 12/20/2010
• Status: Active Grant

• Current Assignee: Roswell Me Incorporated
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Jin, Sungho, Choi, Chulmin
• Granted Patent: US 9,956,743 B2
• Time in Patent Office: Days
• US Class Current: 428/297.4
• CPC Class Codes: A01N 25/34 Shaped forms, e.g. sheets, not provided for in any other sub-group of this main group
• CPC Class Codes: B05D 5/00 Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
• CPC Class Codes: B05D 5/08 to obtain an anti-friction or anti-adhesive surface rendering particulate materials free-flowing in general, e.g. making them hydrophobic B01J2/30
• CPC Class Codes: B05D 5/083 involving the use of fluoropolymers
• CPC Class Codes: B81B 2203/0361 Tips, pillars
• CPC Class Codes: B81B 2207/11 Structural features, others than packages, for protecting a device against environmental influences
• CPC Class Codes: B81C 1/00111 Tips, pillars, i.e. raised structures microneedles A61M37/0015
• CPC Class Codes: B81C 1/00206 Processes for functionalising a surface, e.g. provide the surface with specific mechanical, chemical or biological properties
• CPC Class Codes: B81C 1/00404 Mask characterised by its size, orientation or shape
• CPC Class Codes: B81C 1/00428 Etch mask forming processes not provided for in groups B81C1/00396 - B81C1/0042
• CPC Class Codes: B81C 1/00531 Dry etching
• CPC Class Codes: B82B 3/0038 Manufacturing processes for forming specific nanostructures not provided for in groups B82B3/0014 - B82B3/0033
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C23C 22/66 Treatment of aluminium or alloys based thereon
• CPC Class Codes: C23C 22/83 Chemical after-treatment
• CPC Class Codes: C23C 2222/20 Use of solutions containing silanes
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3086 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/02366 : of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
• CPC Class Codes: Y02E 10/50 : Photovoltaic [PV] energy
• CPC Class Codes: Y10T 428/249924 : Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
• CPC Class Codes: Y10T 428/24994 : Fiber embedded in or on the surface of a polymeric matrix

Abstract

Devices, systems and techniques are described for producing and implementing articles and materials having nano-scale and microscale structures that exhibit superhydrophobic, superoleophobic or omniphobic surface properties and other enhanced properties. In one aspect, a surface nanostructure can be formed by adding a silicon-containing buffer layer such as silicon, silicon oxide or silicon nitride layer, followed by metal film deposition and heating to convert the metal film into balled-up, discrete islands to form an etch mask. The buffer layer can be etched using the etch mask to create an array of pillar structures underneath the etch mask, in which the pillar structures have a shape that includes cylinders, negatively tapered rods, or cones and are vertically aligned. In another aspect, a method of fabricating microscale or nanoscale polymer or metal structures on a substrate is made by photolithography and/or nano imprinting lithography.

Claims

1. A method of fabricating a material with a pillar array surface, comprising:

depositing a buffer layer of a buffer layer material on a substrate material, wherein the buffer layer material is a silicon-containing material;

adding a film layer over the buffer layer;

annealing the film layer to form balled-up structures that are distributed in an array of balled-up islands over the buffer layer to produce an etch mask; and

etching the buffer layer using the etch mask to create an array of pillar structures of the buffer layer material underneath the etch mask, wherein the pillar structures have a shape that includes at least one of a substantially straight cylinder, negatively tapered rod, or cone and are aligned substantially vertical.

2. The method of claim 1, wherein the pillar array surface exhibits superhydrophobic, superoleophobic, or superomniphobic surface properties.

6. The method of claim 1, further comprising etching partially into the substrate material using the etch mask to create the array of pillar structures of the buffer layer material and the substrate material underneath the etch mask.

15. The method of claim 1, wherein the substrate material includes at least one of silicon (Si), silicon-germanium (Si—

Ge), zinc oxide (ZnO), gallium nitride (GaN), gallium arsenide (GaAs), sapphire, window glass, solar cell cover glass, soda lime silicate glass, quartz, alkaline earth boro-aluminosilicate, sodium boro-silicate glass, Pyrex glass, carbon, graphite, nitride, oxide, fluoride, or a metal, semiconductor, ceramic or polymer material.

3-5. -5. (canceled)

7-14. -14. (canceled)

16-27. -27. (canceled)

28. A method of fabricating a superhydrophobic coating on a surface, comprising:

depositing at least one layer of paint on the surface;

utilizing a nano imprinting process comprising;

imprinting a stamp on the surface when the paint is partially dry, wherein the stamp has an arrangement of nano pillar tips on its surface, and

releasing the stamp, whereby a nanostructure imprint in the shape of the nano pillar tips is imprinted on the surface; and

depositing a thin layer of a coating material over the surface.

34. The method of claim 28, wherein the stamp is a flat or roller-type shape.

36. The method of claim 28, wherein the coating material is palladium (Pd).

39. The method of claim 28, wherein the superhydrophobic coating has properties including corrosion resistant, self-cleaning surface characteristics, water repellent, and water droplet contact angle of at least 150°

.

29-33. -33. (canceled)

35. (canceled)

37-38. -38. (canceled)

40-43. -43. (canceled)

44. A method of fabricating a superomniphobic coating on a surface of a solar cell panel, comprising:

depositing a uniform layer of a paste or slurry on the surface of the solar cell panel, wherein the paste or slurry comprises nanoparticles mixed with a precursor, a binder, and a solvent;

utilizing a nano imprinting process comprising;

imprinting a stamp into the uniform layer when the paste or slurry is partially dry, wherein the stamp includes an array of nano pillar structures that have nano pillar tips, and

releasing the stamp, whereby a nanostructure imprint having a shape of the array of nano pillar tips is imprinted into the uniform layer;

curing or drying the uniform layer; and

depositing a thin layer of a coating material over the surface.

45. The method of claim 44, wherein the nanoparticles are selected from glass, silica, or titania nanoparticles.

55. The method of claim 44, wherein the superomniphobic coating has properties including self-cleaning surface characteristics, strong light absorption, and optical transparency.

46-54. -54. (canceled)

56. A device comprising an enhanced nanostructure surface that includes TiO₂ nanotubes on a substrate with enhanced superhydrophobic or superomniphobic surface characteristics, wherein the enhanced nanostructure surface forms at least a 170°

contact angle of a water droplet.

57. The device of claim 56, wherein the TiO₂ nanotubes have a pillar shape or cone shape.

58. The device of claim 56, wherein the enhanced nanostructure surface is further coated with a Teflon layer, fluoroalkysilane (FAS) layer, or a layer of a polymer material having a CF₃-terminal group.

59. The device of claim 56, wherein the enhanced nanostructure surface is a composite material comprising TiO₂ nanotubes in a matrix polymer.

60. The device of claim 59, wherein the composite material is transparent or translucent.

61. The device of claim 59, wherein the enhanced nanostructure surface is further coated with a Teflon layer, FAS layer, or a layer of a polymer material having a CF₃-terminal group.

62. A device comprising an enhanced superhydrophobic and superomniphobic surface, comprising:

a substrate;

an adhesion layer on the substrate;

a deposition material on the adhesion layer; and

a layer of nanowire structures grown on the deposition material.

66. The device of claim 62, wherein the nanowire structures are zinc oxide nanowires.

67. The device of claim 66, wherein the zinc oxide nanowires have a diameter of substantially 100 nm and a height of substantially 2 μ

m.

68. The device of claim 62, wherein the nanowire structures are silicon oxide nanowires.

69. The device of claim 68, wherein the silicon oxide nanowires have a diameter of substantially 100 nm and a height of substantially 2 μ

m.

70. The device of claim 62, wherein the enhanced superhydrophobic and superomniphobic surface has properties including water repellent, non-wetting, and water droplet contact angle of at least 170°

.

63-65. -65. (canceled)

71-97. -97. (canceled)

98. A method of fabricating an anti-fingerprint surface coating structure, comprising:

depositing a transparent buffer layer of a buffer layer material on a transparent substrate material, wherein the transparent buffer layer material is a silicon-containing material;

adding a mask layer of a mask layer material over the transparent buffer layer, wherein the adding includes patterning the mask layer material to form a patterned mask; and

etching the transparent buffer layer using the patterned mask to create an array of pillar structures of the transparent buffer layer material underneath the patterned mask, wherein the pillar structures have a shape that includes at least one of a substantially straight cylinder, negatively tapered rod, or cone and are aligned substantially vertical.

103. The method of claim 98, further comprising coating the array of pillar structures with a hydrophobic layer of a hydrophobic material.

99-102. -102. (canceled)

104-110. -110. (canceled)