Graphene membrane laminated to porous woven or nonwoven support
Technologies are generally described for composite membranes which may include a porous graphene layer in contact with a porous support substrate. In various examples, a surface of the porous support substrate may include at least one of: a thermo-formed polymer characterized by a glass transition temperature, a woven fibrous membrane, and/or a nonwoven fibrous membrane. Examples of the composite membranes permit the use of highly porous woven or nonwoven fibrous support membranes instead of intermediate porous membrane supports. In several examples, the composite membranes may include porous graphene layers directly laminated onto the fibrous membranes via the thermo-formed polymers. The described composite membranes may be useful for separations, for example, of gases, liquids and solutions.
1. A method to prepare a composite membrane, the method comprising:
contacting a first surface of a porous graphene layer to a growth substrate;
contacting a second surface of the porous graphene layer to a first surface of a fibrous porous support substrate, wherein the fibrous porous support substrate is comprised of woven or non-woven fibrous material;
removing the porous graphene layer with the fibrous porous support substrate from the growth substrate;
contacting a surface of the fibrous porous support substrate to a porous metal support, wherein the porous metal support includes one or more of a metal grid and a spiral bound mesh; and
heating the porous graphene layer and the fibrous porous support substrate to form the composite membrane using a pressurized thermoforming process, wherein the pressurized thermoforming process includes a hot calendaring process.
2. The method of claim 1 , further comprising:
selecting the woven or non-woven fibrous material such that the fibrous porous support substrate includes a distribution of pores with an average pore diameter in a range between 5 nanometers and 250 micrometers.
3. The method of claim 1 , further comprising:
selecting the woven or non-woven fibrous material such that the fibrous porous support substrate includes a distribution of pores, wherein less than one pore per billion in the distribution of pores has a diameter greater than 4 times an average pore diameter.
4. The method of claim 1 , further comprising:
contacting the fibrous porous support substrate to at least one woven fibrous membrane or at least one nonwoven fibrous membrane.
5. The method of claim 1 , wherein the first surface of the fibrous porous support substrate is softened and a surface contact between the second surface of the porous graphene layer and the first surface of the fibrous porous support substrate is increased, in response to heating the porous graphene layer and the fibrous porous support substrate to form the composite membrane using the pressurized thermoforming process.
6. The method of claim 1 , wherein the porous graphene layer includes a first set of pores, the fibrous porous support substrate includes a second set of pores, and the first set of pores fail to occlude the second set of pores as a surface contact between the second surface of the porous graphene layer and the first surface of the fibrous porous support substrate is increased.