Transparent and insulating materials having evacuated capsules

Patent metadata

Field	Value
Publication number	US-10865136-B2
Application number	US-201715656378-A
Country	US
Kind code	B2
Filing date	Jul 21, 2017
Priority date	Jul 22, 2016
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

Transparent and insulating materials having evacuated capsules are provided. According to an aspect of the invention, a method includes forming evacuated capsules within a solution, and dispersing and suspending the evacuated capsules within the solution such that a packing density of the evacuated capsules within the solution is greater than 30%, and a visible light transmission of the solution including the evacuated capsules is greater than 75%. According to another aspect of the invention, a layer includes a plurality of evacuated capsules distributed within a dried sol-gel. A thermal conductivity of the layer is between 0.02 W/m-K and 0.001 W/m-K, and the layer has a visible light transmission of greater than 30%.

First claim

The invention claimed is:

1. A method comprising:
forming a composition consisting essentially of a plurality of hollow spherical silica shells within a solution;
dispersing and suspending the hollow spherical silica shells within the solution such that a packing density of the hollow spherical silica shells within the solution is greater than 30%, and a visible light transmission of the solution is greater than 75%;
processing the solution with a sol-gel method; and
drying the processed solution to form a secondary shell of silica, wherein:
the hollow spherical silica shells are integrated by the secondary shell to form a layer consisting essentially of the hollow spherical silica shells and the secondary shell,
at least a portion of the hollow spherical silica shells have an internal volume at a pressure of less than 1 microtorr,
each hollow spherical silica shell has a lateral dimension between 50 nm and 300 nm,
the layer has a thickness between 3.175 mm and 6.35 mm,
the layer has a thermal conductivity between 0.001 W/m-K and 0.02 W/m-K, and
the layer has a visible light transmission of greater than 30% and less than 70%.

2. The method of claim 1 , wherein the dispersing and suspending comprises:
adjusting a pH of the solution to a value between 9 and 14, and
adding a polycation or a polyanion to the solution.

3. The method of claim 1 , wherein the packing density is greater than 70%.

4. The method of claim 1 , further comprising adding a strengthening agent to the solution before processing the solution.

5. The method of claim 4 , wherein the strengthening agent comprises at least one of poly(vinyl alcohol) or boric acid.

6. The method of claim 1 , wherein the forming comprises:
creating a template using dodecanethiol and cetyl-trimethylammonium bromide;
coating the template with a silica-gel; and
heating the template to a temperature of at least 250° C. in vacuum, resulting in the hollow spherical silica shells.

7. The method of claim 6 , wherein the forming further comprises performing atomic layer deposition, physical vapor deposition, chemical vapor deposition, or solution phase deposition to deposit a low-emissivity coating on the hollow silica shells.

8. The method of claim 1 , wherein each of the hollow spherical silica shells has a lateral dimension between 50 nm and 300 nm.

9. The method of claim 8 , wherein the lateral dimension is between 80 nm and 100 nm.

10. A composition comprising:
a layer consisting essentially of:
a plurality of hollow spherical primary silica shells; and
a secondary shell of silica integrated with the hollow spherical primary silica shells to form the layer, wherein:
each hollow spherical primary silica shell has a lateral dimension between 50 nm and 300 nm,
at least a portion of the hollow spherical primary silica shells have an internal volume at a pressure of less than 1 microtorr,
the layer has a thickness between 3.175 mm and 6.35 mm,
the layer has a thermal conductivity between 0.001 W/m-K and 0.02 W/m-K; and
the layer has a visible light transmission of greater than 30% and less than 70%.

11. The composition of claim 10 , wherein the lateral dimension is between 80 nm and 100 nm.

12. The composition of claim 10 , wherein at least a portion of the hollow spherical primary silica shells are concave.

13. The composition of claim 10 , wherein at least a portion of the hollow spherical primary silica shells has thickness between 3 nanometers and 20 nanometers.

14. The composition of claim 10 , wherein the secondary shell has a shape that is substantially cylindrical.

15. The composition of claim 10 , further comprising boric acid, wherein the boric acid strengthens the layer.

16. The composition of claim 10 , wherein at least a portion of the hollow spherical primary silica shells and the secondary shell form a pore.

17. The composition of claim 10 , wherein the secondary shell is produced by a sol-gel method.

Assignees

• Alliance Sustainable Energy

Inventors

• Simpson Lin Jay
• Engtrakul Chaiwat

Classifications

• C03C2217/216

  ZnO · CPC title

• C01P2004/32

  Spheres · CPC title

• C03C11/002 Primary

  Hollow glass particles · CPC title

• C03C2217/211

  SnO2 · CPC title

• C03C17/2453 Primary

  Coating containing SnO2 · CPC title