Antireflective synthetic brochosomal coatings

Patent metadata

Field	Value
Publication number	US-2018292579-A1
Application number	US-201815946004-A
Country	US
Kind code	A1
Filing date	Apr 5, 2018
Priority date	Apr 5, 2017
Publication date	Oct 11, 2018
Grant date	—

Abstract

Synthetic brochosomes can be prepared by disposing a monolayer of first polymer microspheres on a substrate and forming a layer of metal on the monolayer of the first polymer microspheres. A monolayer of second polymer microspheres is then disposed on the layer of metal to form a template. The second polymer microspheres are smaller than the first polymer microspheres. A brochosome material is then electrodeposited on the template. The brochosome material is selected from the group consisting of a metal, a metal oxide, a polymer or a hybrid thereof. The first polymer microspheres and the second polymer microspheres are then removed to form a coating of synthetic brochosomes of the brochosome material on the substrate.

First claim

What is claimed is:

1 . Synthetic brochosomes comprising:
one or more microspheres having surface indentations arranged in a pattern, wherein the brochosomes comprise a metal, a metal oxide, an electrically conducting polymer, and combinations thereof.

2 . The brochosomes of claim 1 , wherein the microspheres have a length scale in a range from 1 um to 10 μm. 3, The brochosomes of claim 1 , wherein the surface indentations have a length scale of 100 nm to 1 μm.

4 . The brochosomes of claim 1 , wherein the pattern in which the surface indentations are arranged is a honeycomb pattern.

5 . The brochosomes of claim 1 , wherein a ratio (R t /R b ) of a radius of R t of the surface indentations on a given microsphere to a radius R b of the given microsphere is less than 0.35.

6 . The brochosomes of claim 1 , wherein ˜9λ>R b >˜1.4λ (λ is wavelength of the electromagnetic waves) and ˜2λ>R t >˜0.5λ.

7 . An antireflective coating comprising a layer of synthetic brochosomes of claim 1 disposed on a substrate.

8 . The antireflective coating of claim 7 , wherein the substrate is electrically conductive.

9 . The antireflective coating of claim 7 , wherein the layer is a monolayer of synthetic brochosomes.

10 . The antireflective coating of claim 7 , wherein the coating has a reflectance of less than 10% at a wavelength in a range from 250 nm to 2000 nm.

11 . The antireflective coating of claim 7 , wherein the synthetic brochosomes are disposed in the layer in substantially a honeycomb pattern.

12 . A method of preparing synthetic brochosomes, the method comprising:
disposing a layer of first removable spheres on a substrate; forming a layer of an electrically conductive material on the layer of first removable spheres; disposing a layer of second removable spheres on the layer of electrically conductive material to form a template, the second removable spheres being smaller the first removable spheres; electrodepositing a brochosome material on the template, and removing the first removable spheres and the second removable spheres to form synthetic brochosomes of the brochosome material.

13 . The method of claim 12 , further comprising isotropic etching of the first removable spheres prior to electrodepositing the brochosome material, and removing the first and the removable spheres to reduce the size of the first and removable spheres, thereby releasing the synthetic brochosomes from the substrate following the removing of the first and second removable spheres.

14 . The method of claim 12 , wherein disposing the layer of first spheres on the substrate comprises:
disposing the first removable spheres on an intermediate substrate; forming a free-standing monolayer of the first removable spheres at an interface of a liquid and air by immersing the intermediate substrate in the liquid, the liquid having a specific gravity greater than that of the first removable spheres and the liquid being substantially inert to the first removable spheres; and transferring the free-standing monolayer onto the substrate.

15 . The method of claim 14 , wherein the first removable spheres comprise polystyrene and the liquid is an aqueous medium.

16 . The method of claim 12 , wherein
the brochosome material comprises a metal, and during electrodepositing the brochosome material, the electrically conductive material of the template is used as a cathode.

17 . The method of claim 12 , wherein
the brochosome material is a metal oxide or a conducting polymer, and during electrodepositing the brochosome material, the electrically conductive material of the template is used as an anode.

18 . The method of claim 12 , wherein the first removable spheres have a length scale in a range from 1 μm to 10 μm.

19 . The method of claim 12 , wherein the second removable spheres have a length scale of 100 nm to 1 μm.

20 . The method of claim 12 , wherein a ratio (R t /R b ) of a radius of R t of the second removable spheres to a radius R b of the first removable spheres is less than 0.35.

Assignees

• Penn State Res Found

Inventors

• Wong Tak-Sing
• Yang Shikuan
• Sun Nan
• Boschitsch Birgitt

Classifications

• C25D13/06

  with polymers {(not used, see C09D5/44)} · CPC title

• C25D5/605

  Surface topography of the layers, e.g. rough, dendritic or nodular layers · CPC title

• B22F1/18

  Non-metallic particles coated with metal · CPC title

• G02B1/118

  having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures · CPC title

• B22F1/05

  Metallic powder characterised by the size or surface area of the particles · CPC title