Liquid processing of 2D materials
One strength of liquid phase exfoliation is that it yields nanosheets dispersed in liquids. This is extremely useful as it facilitates further processing of the nanosheets to create functional structures. For example, polymer-nanosheet composite dispersions can be produced very easily simply by mixing a dispersion of nanosheets with the polymer solution. These composite dispersions can easily be formed into composite films, for example my screen printing. Alternatively, nanosheet dispersions can be mixed with dispersions of other nanomaterials, primarily carbon nanotubes, to produce nano-nano composite dispersions. Again, such compass dispersions can easily be formed into composite films, for example by vacuum filtration, blade coating or screen printing.
Alternatively, thin films containing only nanosheets can be produced by printing. The resultant structures consist of disordered arrays of nanosheets predominantly aligned in the plane of the film and are known as nanosheet networks. Large area networks can be produced easily by spray coating or vacuum filtration. However, if patterned networks are required, this can easily be achieved using either inkjet printing screen printing or aerosol jet printing. Using combinations of these techniques it is possible to produce heterostructures. These are either planar arrangements or vertical stacks of networks of dissimilar nanosheets. Heterostructures are the basis of many devices.