Reduced graphene oxide barrier materials

Abstract

This invention relates to barrier materials comprising reduced graphene oxide, methods of making said materials and their uses. The reduced graphene oxide is preferably formed from the reduction of graphene oxide by HI, HBr or ascorbic acid.

1 . A method of making a barrier material, the method comprising reducing a graphene oxide laminate membrane to form a reduced graphene oxide laminate membrane with a reducing agent, wherein the reducing agent does not generate CO 2  or CO as a major component when it reduces graphene oxide. 
     
     
         2 . The method of  claim 1 , wherein the reducing agent is selected from the group consisting of HI, HBr and ascorbic acid (vitamin C). 
     
     
         3 . The method of  claim 1 , wherein the method further comprises:
 (A) supporting the graphene oxide laminate membrane on a substrate; and   (B) reducing the graphene oxide laminate membrane to form the reduced graphene oxide laminate membrane supported on the substrate.   
     
     
         4 . The method of  claim 3 , wherein step (A) further comprises depositing a graphene oxide suspension onto the substrate to form the graphene oxide laminate membrane supported on the substrate. 
     
     
         5 . The method of  claim 3 , wherein the method further comprises, before the graphene oxide laminate membrane is supported on the substrate (step (A)), modifying the substrate to increase the strength of the association between the substrate and the graphene oxide and/or reduced graphene oxide laminate membrane. 
     
     
         6 . The method of  claim 5 , wherein modifying the substrate comprises coating the surface of the substrate with an adhesion promoter. 
     
     
         7 . The method of  claim 5 , wherein the substrate is a polymer substrate and the step of modifying the substrate comprises oxidising the surface of the substrate by exposing it to ozone and/or oxygen plasma to form an oxidised polymer substrate. 
     
     
         8 . The method of  claim 7 , wherein the polymer substrate is poly(ethylene terephthalate) (PET). 
     
     
         9 . The method of  claim 3 , wherein the substrate is a porous structure or material and the method is a method of reducing the porosity of a porous structure or material. 
     
     
         10 . The method of  claim 2 , wherein the reducing agent is ascorbic acid (vitamin C). 
     
     
         11 . The method of  claim 6 , wherein the adhesion promoter is a polymer. 
     
     
         12 . The method of  claim 5 , wherein the adhesion promoter is selected from the group consisting of phytic acid, PMMA, poly(vinyl alcohol) (PVA), polystyrene, poly(4-styrenesulfonate), Nafion, carboxymethyl cellulose, chitosan, polyvinyl pyrrolidone and polyaniline. 
     
     
         13 . The method of  claim 5 , wherein the substrate is a metal substrate and the adhesion promoter is selected from the group consisting of phytic acid, poly(methyl methacrylate) (PMMA) and polystyrene. 
     
     
         14 . The method of  claim 6 , wherein the substrate is a glass or silicon-based substrate and the adhesion promoter is sodium metasilicate. 
     
     
         15 . The method of  claim 3 , wherein the method further comprises:
 C) transferring the reduced graphene oxide laminate membrane from the first substrate to a second substrate.   
     
     
         16 . The method of  claim 1 , wherein the method further comprises the step of rinsing the reduced graphene oxide laminate membrane with a rinsing agent. 
     
     
         17 . The method of  claim 1 , wherein the method further comprises the step of drying the reduced graphene oxide laminate membrane after the reduction step. 
     
     
         18 . The method of  claim 1 , wherein the step of reducing the graphene oxide laminate membrane takes place at a temperature from about −5° C. to about 150° C. 
     
     
         19 . The method of  claim 1 , wherein the step of reducing the graphene oxide laminate membrane takes from about 0.5 minutes to about 120 hours. 
     
     
         20 . A barrier material prepared according to the method of  claim 1 .