Graphite Exfoliation Method

Patent metadata

Field	Value
Publication number	US-2017029280-A1
Application number	US-201415106793-A
Country	US
Kind code	A1
Filing date	Dec 11, 2014
Priority date	Dec 19, 2013
Publication date	Feb 2, 2017
Grant date	—

Abstract

A method of producing an aqueous dispersion of few-layer graphene nanosheets is disclosed, the method including: (a) mixing graphite particles with a perfluorosulfonate ionomer in an aqueous liquid, to form an aqueous dispersion of graphite particles; and (b) sonicating the aqueous dispersion of graphite particles to form an aqueous dispersion of few-layer graphene nanosheets, wherein the perfluorosulfonate ionomer is disposed as a thin and continuous layer on the few-layer graphene nanosheets. A composition is also disclosed, comprising an aqueous dispersion of a mixture of: (a) a perfluorosulfonate ionomer; and (b) a plurality of few-layer graphene nanosheets; wherein the perfluorosulfonate ionomer is disposed as a thin and continuous layer on the few-layer graphene nanosheets.

First claim

1 . A method of producing an aqueous dispersion of few-layer graphene nanosheets, the method comprising:
(a) mixing graphite particles with a perfluorosulfonate ionomer in an aqueous liquid, to form an aqueous dispersion of graphite particles; and (b) sonicating the aqueous dispersion of graphite particles to form an aqueous dispersion of few-layer graphene nanosheets;
wherein the perfluorosulfonate ionomer is disposed as a thin and continuous layer on the few-layer graphene nanosheets.

2 . The method of claim 1 , wherein, prior to the sonicating, a concentration of the graphite particles in the aqueous dispersion of graphite particles is in a range from 0.5 mg/mL to 5 mg/mL, relative to a total volume of the aqueous dispersion of graphite particles.

3 . The method of claim 1 or claim 2 , wherein prior to the sonicating, a weight ratio of the perfluorosulfonate ionomer to the graphite particles in the aqueous dispersion of graphite particles is in a range from 0.1:1 to 10:1.

4 . The method of claim 1 , wherein the aqueous dispersion of few-layer graphene nanosheets further comprises a water-miscible solvent.

5 . The method of claim 1 , wherein the water-miscible solvent is a C1 to C4 alcohol.

6 . The method of claim 5 , wherein the water-miscible solvent is ethanol.

7 . The method of claim 1 , wherein a volume ratio of the ethanol and water in the aqueous dispersion of few-layer graphene nanosheets is in a range from 0.5:1 to 1.5:1.

8 . The method of claim 1 , wherein the sonicating is carried out for no more than 24 hours.

9 . The method of claim 1 , wherein the aqueous dispersion of few-layer graphene nanosheets remains dispersed for a period of at least one month after the sonicating.

10 . The method of claim 1 not including the use of any reducing agent and/or oxidizing agent.

11 . The method of claim 1 , wherein the continuous and thin layer of perfluorosulfonate ionomer has a thickness in a range of 2 nm to 100 nm.

12 . A composition comprising an aqueous dispersion of a mixture of:
(a) a plurality of few-layer graphene nanosheets; and (b) a perfluorosulfonate ionomer;
wherein the perfluorosulfonate ionomer is disposed as a continuous and thin layer on few-layer graphene nanosheets in the plurality of few-layer graphene nanosheets.

13 . The composition of claim 12 , wherein the plurality of few-layer graphene nanosheets is present in a range from 0.5 mg/mL to 5 mg/mL, relative to a total volume of the aqueous dispersion.

14 . The composition of claim 12 , wherein a weight ratio of the perfluorosulfonate ionomer to the few-layer graphene nanosheets is in a range from 0.1:1 to 10:1.

15 . The composition of claim 12 , wherein the aqueous dispersion further comprises a water-miscible solvent.

16 . The composition of claim is, wherein the water-miscible solvent is a C1 to C4 alcohol.

17 . The composition of claim 15 , wherein a volume ratio of the water-miscible solvent and water in the aqueous dispersion is in a range from 0.5:1 to 1.5:1.

18 . The composition of claim 12 , wherein the aqueous dispersion has a lifetime as a stable dispersion of at least one month.

19 . The composition of claim 12 , wherein the continuous and thin layer of perfluorosulfonate ionomer has a thickness in a range of 2 nm to 100 nm.

20 . A method of providing a coated article, the method comprising:
(a) providing a substrate; and (b) applying the composition of claim 12 to the substrate.

Assignees

• 3M Innovative Properties Co

Inventors

• Julius David
• Zin Melvin
• Divigalpitiya Ranjith
• Korba Gary A

Classifications

• C08K7/00

  Use of ingredients characterised by shape · CPC title

• C08K2201/011

  Nanostructured additives · CPC title

• C08K3/04 Primary

  Carbon · CPC title

• C09D5/24

  Electrically-conducting paints {(conductive materials H01B1/00)} · CPC title

• C09D127/12

  containing fluorine atoms · CPC title