Methods for conductive adhesives based on graphene and applications thereof

Patent metadata

Field	Value
Publication number	US-12275879-B2
Application number	US-202117189457-A
Country	US
Kind code	B2
Filing date	Mar 2, 2021
Priority date	Dec 1, 2017
Publication date	Apr 15, 2025
Grant date	Apr 15, 2025

Abstract

The present disclosure relates to conductive adhesives and inks. The disclosed conductive adhesives include glues and epoxies, based on graphene and graphene/carbon composites and the methods of manufacture thereof, such conductive adhesives exhibiting excellent conductivity, thermal properties, durability, low curing temperatures, mechanical flexibility, and reduced environmental impact. Further, adhesives with conductive additives such as silver nanowires and the methods of production thereof are disclosed herein.

First claim

The invention claimed is:

1. A method of forming silver nanowires comprising:
(a) heating a solvent;
(b) adding a catalyst solution;
(c) heating the solvent and the catalyst solution:
(d) adding a polymer solution having a concentration of about 0.075 M to about 0.25 M to the solvent and the catalyst solution to form a first solution;
(e) injecting a silver-based solution into the first solution of step (d) to form a second solution;
(f) centrifuging the second solution; and
(g) washing the second solution with a washing solution to extract the silver nanowires.

2. The method of claim 1 , wherein the solvent comprises a glycol, a polymer solution, or both.

3. The method of claim 1 , wherein the catalyst solution comprises copper (I) chloride, copper (II) chloride, sodium chloride, platinum (II) chloride, silver chloride, iron (II) chloride, iron (III) chloride, tetrapropylammonium chloride, tetrapropylammonium bromide, or any combination thereof.

4. The method of claim 1 , wherein the catalyst solution has a concentration of about 2 mM to about 8 mM.

5. The method of claim 1 , wherein a volume of the solvent is greater than a volume of the catalyst solution by a factor of about 75 to about 250.

6. The method of claim 1 , wherein a volume of the solvent is greater than a volume of the polymer solution by a factor of about 1.5 to about 6.5.

7. The method of claim 1 , wherein the silver-based solution has a concentration of about 0.05 M to about 0.2 M.

8. The method of claim 1 , wherein a volume of the solvent is greater than a volume of the silver-based solution by a factor of about 1.5 to about 6.5.

9. The method of claim 1 , wherein the solvent is heated to a temperature of about 75° C. to about 300° C.

10. The method of claim 1 , wherein the solvent is heated for a period of time of about 30 minutes to about 120 minutes.

11. The method of claim 1 , wherein the solvent is stirred while being heated.

12. The method of claim 11 , wherein the second solution is heated for about 30 minutes to about 120 minutes.

13. The method of claim 1 , wherein the centrifuging occurs at a speed of about 1,500 rpm to about 6,000 rpm.

14. The method of claim 1 , wherein the centrifuging occurs over a period of time of about 10 minutes to about 40 minutes.

15. The method of claim 1 , wherein washing the second solution comprises a plurality of washing cycles comprising from about two cycles to about six cycles.

16. The method of claim 1 , wherein one or more of steps (a), (b), and (c) are performed in a solvothermal chamber.

17. The method of claim 1 , capable of producing silver nanowires having:
(a) a diameter of less than about 0.5 μm;
(b) a length of about 10 μm to about 75 μm; or
(c) both.

18. The method of claim 1 , further comprising heating the second solution before centrifuging the second solution.

19. The method of claim 1 , further comprising cooling the second solution before centrifuging the second solution.

Assignees

• Univ California
• Nanotech Energy Inc

Inventors

• El-Kady Maher F
• Mohamed Nahla
• Kavanaugh Jack
• Kaner Richard B

Classifications

• C08K7/00

  Use of ingredients characterised by shape · CPC title

• C08K2201/001

  Conductive additives · CPC title

• C09D11/322

  Pigment inks · CPC title

• C09D11/037

  characterised by the pigment · CPC title

• C08K2201/011

  Nanostructured additives · CPC title