Sorting two-dimensional nanomaterials by thickness

Patent metadata

Field	Value
Publication number	US-10179841-B2
Application number	US-201615236754-A
Country	US
Kind code	B2
Filing date	Aug 15, 2016
Priority date	Aug 14, 2009
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

The Present teachings provide, in part, methods of separating two-dimensional nanomaterials by atomic layer thickness. In certain embodiments, the present teachings provide methods of generating graphene nanomaterials having a controlled number of atomic layer(s).

First claim

We claim:

1. A method of preparing an aqueous graphene dispersion, said method comprising:
providing a composition comprising a graphite composition comprising natural graphene, at least one non-ionic surface active polymeric component and an aqueous medium;
sonicating said composition to exfoliate said graphite composition and disperse said graphene component within said aqueous medium; and
centrifuging said sonicated composition to separate said dispersed graphene component therefrom.

2. The method of claim 1 wherein said polymeric component comprises a block copolymer of oxyethylene and oxypropylene.

3. The method of claim 1 wherein said centrifugation separates at least one fraction of said dispersed graphene component, said fraction enriched with graphene of a specific thickness dimension.

4. The method of claim 3 comprising isolation of said separation fraction, providing a composition of said separation fraction and at least one non-ionic surface active polymeric component and repeating said centrifugation.

5. A method of using a surface active block copolymeric component to affect dispersion of graphene in an aqueous medium, said method comprising:
providing a composition comprising a graphite composition comprising a graphene component, at least one surface active non-ionic block copolymer of oxyethylene and oxypropylene and an aqueous medium;
sonicating said composition to exfoliate said graphite composition and disperse said graphene component within said aqueous medium; and
centrifuging said sonicated composition to separate said dispersed graphene component therefrom.

6. The method of claim 5 wherein said centrifugation separates at least one fraction of said dispersed graphene component, said fraction enriched with graphene of a specific thickness dimension.

7. The method of claim 6 comprising isolation of said separation fraction, providing a composition of said separation fraction and at least one surface active non-ionic block copolymer of oxyethylene and oxypropylene and repeating said centrifugation.

8. A method of using a density gradient to separate graphene by thickness dimension, said method comprising;
providing a composition comprising a graphite composition comprising a graphene component, at least one surface active non-ionic block copolymer of oxyethylene and oxypropylene and an aqueous medium;
sonicating said composition to exfoliate said graphite composition and disperse said graphene component within said aqueous medium, said dispersed graphene component polydisperse in thickness dimension;
contacting a said dispersed graphene component with a fluid medium comprising a density gradient, and centrifuging said dispersed graphene component and said block copolymer to induce a graphene buoyant density of a density along said gradient and enrich a fraction of said graphene with a specific thickness dimension therein; and
separating said fraction enriched with graphene of a specific thickness dimension.

9. The method of claim 8 wherein said fluid medium comprises a plurality of aqueous iodixanol concentrations, said density gradient comprising a range of iodixanol concentration densities.

10. The method of claim 9 wherein a fraction of said graphene dispersion is isopycnic at a position along said density gradient.

11. The method of claim 8 comprising isolation of said separation fraction, providing a composition of said separation fraction and at least one surface active non-ionic block copolymer of oxyethylene and oxypropylene and repeating said centrifugation.

12. A method of using a density gradient to separate graphene by thickness dimension, said method comprising;
contacting a composition comprising a graphite composition comprising a graphene component polydisperse in thickness dimension and at least one surface active non-ionic block copolymer of oxyethylene and oxypropylene with a fluid medium comprising a density gradient, and centrifuging said composition to induce a graphene buoyant density of a density along said gradient and enrich a fraction of said graphene component with a specific thickness dimension therein; and
separating said fraction enriched with graphene of a specific thickness dimension.

13. The method of claim 12 wherein said fluid medium comprises a plurality of aqueous iodixanol concentrations, said density gradient comprising a range of iodixanol concentration densities.

14. The method of claim 13 wherein a fraction of said graphene dispersion is isopycnic at a position along said density gradient.

15. The method of claim 12 comprising isolation of said separation fraction, providing a composition of said separation fraction and at least one surface active non-ionic block copolymer of oxyethylene and oxypropylene and repeating said centrifugation.

16. A graphene composition comprising graphene complexed with a non-ionic tetrafunctional block copolymer of oxyethylene and oxypropylene.

17. The composition of claim 16 in an aqueous medium.

Assignees

• Univ Northwestern

Inventors

• Green Alexander A
• Hersam Mark C

Classifications

• C01B2204/04

  Specific amount of layers or specific thickness · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C01B32/194

  After-treatment · CPC title

• C01G41/00

  Compounds of tungsten · CPC title

• Y10T436/25375

  Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.] · CPC title