Method of forming a film of graphite oxide single layers, and applications of same

• US 20100239869A1
• Filed: 03/22/2010
• Published: 09/23/2010
• Est. Priority Date: 03/20/2009
• Status: Active Grant

• Current Assignee: Northwestern University
• Original Assignee: Northwestern University
• Inventors: Kim, Franklin J., Cote, Laura J., Huang, Jiaxing
• Granted Patent: US 9,118,078 B2
• Time in Patent Office: Days
• US Class Current: 428/426
• CPC Class Codes: H01M 4/663 containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
• CPC Class Codes: H01M 4/667 in the form of layers, e.g. coatings
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

A method for forming a film of graphite oxide single layers. In one embodiment, the method includes the steps of preparing a solution of graphite oxide to allow a plurality of graphite oxide single layers to be formed and dispersed in the solution; and applying the solution of graphite oxide onto an air-water interface of water to form a film at the air-water interface, wherein the film comprises a plurality of graphite oxide single layers and is characterized by a packing density, wherein the film of graphite oxide single layers is formed with no presence of a surfactant or stabilizing agent.

Claims

1. A method of forming a film of graphite oxide single layers, comprising the steps of:

(a) preparing a solution of graphite oxide to allow a plurality of graphite oxide single layers to be formed and dispersed in the solution; and

(b) applying the solution of graphite oxide onto an air-water interface of water to form a film at the air-water interface, wherein the film comprises a plurality of graphite oxide single layers and is characterized by a packing density,

wherein the film of graphite oxide single layers is formed with no presence of a surfactant or stabilizing agent.

2. The method of claim 1, wherein a plurality of graphite oxide single layers in the film of graphite oxide single layers each is in monolayer form, further comprising the step of compressing the film of graphite oxide single layers transversally to tune the packing density of the film.

3. The method of claim 2, wherein the packing density of the film can range from (a) dilute monolayers of isolated graphite oxide single layers, to (b) closely-packed monolayers without adjacent monolayers of graphite oxide single layers touching each other, to (c) over-packed monolayers with monolayers of isolated graphite oxide single layers folded at interconnecting edges, and to (d) over-packed monolayers with folded and partially overlapped monolayers of isolated graphite oxide single layers interlocking with each other.

4. The method of claim 1, wherein the preparing step comprises the step of dissolving graphite oxide in a solvent to obtain a solution of graphite oxide.

5. The method of claim 4, wherein the solvent is methanol.

6. The method of claim 5, for the applying step, wherein the ratio of water to methanol is about 1:

5.

7. The method of claim 1, further comprising the step of transferring the film of graphite oxide single layers to a solid substrate.

8. The method of claim 7, wherein the step of transferring comprises the steps of:

(a) immersing the solid substrate in the mixture of the solution and water such that the solid substrate is underneath the film of graphite oxide single layers at the air-water interface; and

(b) pulling the solid substrate up to allow at least part of the film of graphite oxide single layers to be in contact with a surface of the solid substrate such that the surface of the solid substrate is at least partially coated with a layer of graphite oxide single layers.

9. The method of claim 8, wherein the surface of the solid substrate is hydrophilic.

10. The method of claim 9, wherein the substrate is selected from the group consisting of silicon, glass, quartz, and mica.

11. The method of claim 8, further comprising the steps of:

(a) drying the solid substrate after the pulling step;

(b) subsequently immersing the solid substrate in the mixture of the solution and water such that the solid substrate is underneath the film of graphite oxide single layers at the air-water interface to allow the surface that is at least partially coated with a layer of graphite oxide single layers to be proximate to the film of graphite oxide single layers at the air-water interface; and

(c) pulling the solid substrate up to allow at least part of the film of graphite oxide single layers to be in contact with the at least partially coated surface of the solid substrate such that the surface of the solid substrate is at least partially coated with another layer of graphite oxide single layers.

12. The method of claim 11, further comprising the step of repeating the steps (a)-(c) of claim 11 one or more times to coat additional one or more layers of graphite oxide single layers over the at least partially coated surface of the solid substrate.

13. An article of manufacture made by the method of claim 1.

14. A method of forming a conducting film of graphene, comprising the steps of:

(a) preparing a solution of graphite oxide to allow a plurality of graphite oxide single layers to be formed and dispersed in the solution;

(b) applying the solution of graphite oxide onto an air-water interface of water to form a film at the air-water interface, wherein the film comprises a plurality of graphite oxide single layers and is characterized by a packing density;

(c) providing a substrate with a hydrophilic surface;

(d) immersing the substrate in the mixture of the solution and water such that the substrate is underneath the film of graphite oxide single layers at the air-water interface to allow the hydrophilic surface to be proximate to the film of graphite oxide single layers at the air-water interface;

(e) pulling the substrate up to allow at least part of the film of graphite oxide single layers to be in contact with the hydrophilic surface of the substrate such that the hydrophilic surface of the substrate is at least partially coated with a layer of graphite oxide single layers; and

(f) reducing chemically the layer of graphite oxide single layers coated on the hydrophilic surface of the substrate to a conducting film of graphene,

wherein the film of graphite oxide single layers is formed with no presence of a surfactant or stabilizing agent.

15. The method of claim 14, wherein a plurality of graphite oxide single layers in the film of graphite oxide single layers each is in monolayer form, further comprising the step of compressing the film of graphite oxide single layers transversally to tune the packing density of the film.

16. The method of claim 15, wherein the packing density of the film can range from (a) dilute monolayers of isolated graphite oxide single layers, to (b) closely-packed monolayers without adjacent monolayers of graphite oxide single layers touching each other, to (c) over-packed monolayers with monolayers of isolated graphite oxide single layers folded at interconnecting edges, and to (d) over-packed monolayers with folded and partially overlapped monolayers of isolated graphite oxide single layers interlocking with each other.

17. The method of claim 14, wherein the preparing step comprises the step of dissolving graphite oxide in a solvent to obtain a solution of graphite oxide.

18. The method of claim 17, wherein the solvent is methanol.

19. The method of claim 18, for the applying step, wherein the ratio of water to methanol is about 1:

5.

20. The method of claim 14, wherein the substrate is selected from the group consisting of silicon, glass, quartz, and mica.

21. The method of claim 14, further comprising the step of drying the substrate after the pulling step.

22. The method of claim 14, wherein the reducing step comprises the step of exposing the coated substrate to hydrazine vapor.

23. An article of manufacture made by the method of claim 14.

24. An article of manufacture with at least one conducting film of graphene, comprising:

(a) a substrate;

(b) at least one conducting film of graphene; and

(c) at least two electrodes formed in electrical contact with the at least one conducting film of graphene,

wherein the at least one conducting film of graphene is reduced chemically from a film of graphite oxide single layers coated on a surface of the substrate,

wherein the film of graphite oxide single layers is coated on the surface of the substrate by Langmuir-Blodgett assembly, and

wherein the film of graphite oxide single layers is formed with no presence of a surfactant or stabilizing agent.

25. The article of manufacture of claim 24, wherein the substrate is selected from the group consisting of silicon, glass, quartz, and mica.