Method for producing large-area monolayer films of solution dispersed nanomaterials

Abstract

A large-area monolayer of solvent dispersed nanomaterials and method of producing same is provided. The method includes dripping a nanomaterial solvent into a container filled with water whereby the nanomaterial being dripped collects at the air-water interface to produce the large-area monolayer. In one embodiment, different nanomaterial solvents can be dripped, at predetermined intervals such that the resulting large-area monolayer includes at least two different nanomaterials.

1 . A method of producing a substrate coated with a monolayer film of a nanomaterial comprising:
 dispersing a nanomaterial in a water-immiscible solvent to produce a nanomaterial solvent mixture;   dripping, at predetermined time intervals, single drops of the nanomaterial solvent mixture into a water-filled container whereby as each drop of the nanomaterial solvent mixture contacts a surface of the water, the nanomaterial solvent mixture spreads and the solvent evaporates to leave a monolayer film of the nanomaterial floating on the surface of the water at an air-water interface; and   continuously withdrawing the monolayer film from the container at a rate which matches growth rate of the monolayer film and continuously transferring the monolayer film to a substrate of arbitrary length but a width smaller than a width of the container.   
     
     
         2 . The method of  claim 1 , wherein the water-immiscible solvent comprises 1,2-dichloroethane (DCE). 
     
     
         3 . The method of  claim 2 , wherein the water-immiscible solvent further comprises ethanol. 
     
     
         4 . The method of  claim 3 , wherein volume ratio of ethanol:DCE is 1:13. 
     
     
         5 . The method of  claim 1 , wherein the nanomaterial is graphene oxide (GO). 
     
     
         6 . The method of  claim 5 , wherein the substrate comprises a silver nanowire, and the method further comprises reducing the graphene oxide monolayer to a reduced graphene oxide monolayer on the silver nanowire. 
     
     
         7 . The method of  claim 1 , wherein:
 the nanomaterial is a first nanomaterial and the nanomaterial solvent mixture is a first nanomaterial solvent mixture; and,   the method further comprises changing the nanomaterial solvent mixture being dripped by dripping, at predetermined time intervals, single drops of a second nanomaterial solvent mixture comprising a second nanomaterial that is different from the first nanomaterial, into the water-filled container to leave a monolayer film of the second nanomaterial growing from the monolayer of the first nanomaterial film to produce a monolayer film comprising at least two different nanomaterials.   
     
     
         8 . The method of  claim 7 , wherein the second nanomaterial comprises MoS 2 . 
     
     
         9 . The method of  claim 1 , wherein the substrate is a flexible substrate composed of a polymer. 
     
     
         10 . The method of  claim 9 , wherein the polymer comprises polyethylene terephthalate, polyethylene imide, polycarbonate, polymethylmethacrylate or polystyrene. 
     
     
         11 . A substrate coated with a monolayer film produced by the process of  claim 1 .