Abstract: Perforated graphene sheets can be used in forming separation membranes. Separation membranes of the present disclosure, which can be used in gas separation processes in some embodiments, can include one or more layers of perforated graphene and one or more layers of another membrane material. Methods for separating a gas mixture can include contacting a gas mixture with the separation membranes, and transiting one or more of the gases through the perforated graphene so as to affect separation.

Abstract: Production of bulk quantities of graphene for commercial ventures has proven difficult due to scalability issues in certain instances. Plasma-enhanced chemical vapor deposition of graphene can address at least some of these issues. Methods for production of graphene by plasma-enhanced chemical vapor deposition can include: providing a metal substrate and a carbonaceous electrode, at least a portion of the metal substrate being located proximate to the carbonaceous electrode with a gap defined therebetween; applying a potential between the metal substrate and the carbonaceous electrode; exciting a plasma-forming gas in the gap between the metal substrate and the carbonaceous electrode in the presence of the applied potential, thereby forming a plasma; ablating a reactive carbon species from the carbonaceous electrode in the presence of the plasma; and growing graphene on the metal substrate from the reactive carbon species.

Abstract: A method for making a nanoporous membrane is disclosed. The method provides a composite film comprising a two-dimensional material layer and a polymer layer, and then bombarding the composite film with energetic particles to form a plurality of pores through at least the two-dimensional material layer. The nanoporous membrane also has a two-dimensional material layer with a plurality of apertures therethrough and a polymer film layer adjacent one side of the graphene layer. The polymer film layer has a plurality of enlarged pores therethrough, which are aligned with the plurality of apertures. All of the enlarged pores may be concentrically aligned with all the apertures. In one embodiment the two-dimensional material layer is graphene.

Abstract: Multi-layer sheets of graphene-based material having a plurality of pores extending therethrough are described herein. Methods for making the sheets include exposing a graphene-based material comprising multilayer graphene having from 5 to 20 layers of graphene to a particle beam having an ion energy of at least about 1500 eV to create damage tracks in the graphene sheets. The damage tracks in the graphene sheets are then exposed to a chemical etchant, such as an oxidant to define pores through the stacked graphene sheets. Production of the damage tracks and etching of the damage tracks can take place while the graphene is disposed on a substrate.

Abstract: Structures comprising a first sheet of perforated two-dimensional material and a first plurality of spacer elements disposed between a surface of the first sheet of perforated two-dimensional material and at least one of a surface of a structural substrate and a surface of a second sheet of perforated two-dimensional material are disclosed, as well as related methods. The structures may further comprise a structural substrate, a second plurality of spacer elements, additional sheets of perforated two-dimensional material in direct contact with the first and/or said second sheet of perforated two-dimensional material and/or relief features in the surface of the structural substrate.

Abstract: It is often desirable to release graphene from its growth substrate. Present graphene release techniques can damage the graphene and produce significant quantities of hazardous waste. Electrowetting techniques can be used in alternative approaches for releasing graphene from its growth substrate. Methods for releasing graphene by electrowetting can include providing a metal substrate having graphene adhered thereto, applying a dielectric layer to the graphene to form a coated structure, placing the coated structure in a liquid medium, establishing an electrical potential between the metal substrate and a conductor disposed proximate to at least a portion of the dielectric layer such that the electrical potential induces infiltration of the liquid medium between at least a portion of the metal substrate and the graphene, and releasing the graphene from the metal substrate in the presence of the infiltrated liquid medium. The electrical potential can be maintained until the graphene is released.

Abstract: Perforated graphene sheets can be used in forming separation membranes. Separation membranes of the present disclosure, which can be used in gas separation processes in some embodiments, can include one or more polymer layers and one or more layers of perforated graphene. Methods for separating a gas mixture can include contacting a gas mixture with the separation membranes, and transiting one or more of the gases through the perforated graphene so as to affect separation.

Abstract: Articles containing a matrix material and plurality of copper nanoparticles in the matrix material that have been at least partially fused together are described. The copper nanoparticles are less than about 20 nm in size. Copper nanoparticles of this size become fused together at temperatures and pressures that are much lower than that of bulk copper. In general, the fusion temperatures decrease with increasing applied pressure and lowering of the size of the copper nanoparticles. The size of the copper nanoparticles can be varied by adjusting reaction conditions including, for example, surfactant systems, addition rates, and temperatures. Copper nanoparticles that have been at least partially fused together can form a thermally conductive percolation pathway in the matrix material.

Abstract: It can be difficult to remove atomically thin films, such as graphene, graphene-based material and other two-dimensional materials, from a growth substrate and then to transfer the thin films to a secondary substrate. Tearing and conformality issues can arise during the removal and transfer processes. Processes for forming a composite structure by manipulating a two-dimensional material, such as graphene or graphene-base material, can include: providing a two-dimensional material adhered to a growth substrate; depositing a supporting layer on the two-dimensional material while the two-dimensional material is adhered to the growth substrate; and releasing the two-dimensional material from the growth substrate, the two-dimensional material remaining in contact with the supporting layer following release of the two-dimensional material from the growth substrate.

Abstract: Perforating graphene and other two-dimensional materials with holes inclusively having a desired size range, a narrow size distribution, and a high hole density can be difficult to achieve. A layer in continuous contact with graphene, graphene-based materials and other two-dimensional materials can help promote hole formation. Processes for perforating a two-dimensional material can include exposing to an ion source a two-dimensional material in continuous contact with at least one layer, and interacting a plurality of ions from the ion source with the two-dimensional material and with the at least one layer. The ion source may be a broad ion beam.

Abstract: Articles containing a matrix material and plurality of copper nanoparticles in the matrix material that have been at least partially fused together are described. The copper nanoparticles are less than about 20 nm in size. Copper nanoparticles of this size become fused together at temperatures and pressures that are much lower than that of bulk copper. In general, the fusion temperatures decrease with increasing applied pressure and lowering of the size of the copper nanoparticles. The size of the copper nanoparticles can be varied by adjusting reaction conditions including, for example, surfactant systems, addition rates, and temperatures. Copper nanoparticles that have been at least partially fused together can form a thermally conductive percolation pathway in the matrix material.

Abstract: A method for making a nanoporous membrane is disclosed. The method provides a composite film comprising an atomically thin material layer and a polymer layer, and then bombarding the composite film with energetic particles to form a plurality of pores through at least the atomically thin material layer. The nanoporous membrane also has a atomically thin material layer with a plurality of apertures therethrough and a polymer film layer adjacent one side of the graphene layer. The polymer film layer has a plurality of enlarged pores therethrough, which are aligned with the plurality of apertures. All of the enlarged pores may be concentrically aligned with all the apertures. In one embodiment the atomically thin material layer is graphene.

Abstract: A method of forming a filter with uniform pore sizes includes synthesizing a moiety so as to form a plurality of like platelets having a precisely sized pore extending therethrough, distributing the plurality of like platelets about a membrane having apertures therethrough, and bonding the plurality of platelets around the apertures to form precisely sized pores through the membrane. A filtration membrane is also disclosed which provides a porous membrane having a plurality of apertures therethrough, and a plurality of platelets, wherein each platelet has a pore therethrough. The platelets are positioned over or in the apertures.

Abstract: A method for forming a lattice with precisely sized holes includes disposing cutter molecules with species attached about the periphery of each molecule on to the lattice. The method continues with the species cutting molecular bonds of the lattice so as to form precisely sized holes in the lattice. The edges of the holes may then be functionalized.

Abstract: Production of bulk quantities of graphene for commercial ventures has proven difficult due to scalability issues in certain instances. Plasma-enhanced chemical vapor deposition of graphene can address at least some of these issues. Methods for production of graphene by plasma-enhanced chemical vapor deposition can include: providing a metal substrate and a carbonaceous electrode, at least a portion of the metal substrate being located proximate to the carbonaceous electrode with a gap defined therebetween; applying a potential between the metal substrate and the carbonaceous electrode; exciting a plasma-forming gas in the gap between the metal substrate and the carbonaceous electrode in the presence of the applied potential, thereby forming a plasma; ablating a reactive carbon species from the carbonaceous electrode in the presence of the plasma; and growing graphene on the metal substrate from the reactive carbon species.

Abstract: Graphene sheets having a plurality of holes in their basal planes are described herein. Methods for making the graphene sheets can involve contacting graphene sheets with an activated gas that has contacted a helium or argon atmospheric pressure plasma. The size and/or number of holes introduced can be altered by changing the contact time, the stand-off distance, the activated gas concentration, and/or the plasma power. Polymer composites containing the perforated graphene sheets are also described.

Abstract: A method for deionization of a solution, the method comprising functionalizing plural apertures of a graphene sheet to repel first ions in the solution from transiting through the functionalized plural apertures. The non-transiting first ions influence second ions in the solution to not transit through the functionalized plural apertures. The graphene sheet is positioned between a solution flow path input and a solution flow path output. Solution enters the solution flow path input and through the functionalized plural apertures of the graphene sheet, resulting in a deionized solution on the solution flow path output side of the graphene sheet and a second solution containing the first ions and second ions on the solution flow path input side of the graphene sheet.

Abstract: A separation arrangement isolates chlorine, sodium and possibly other ions from water. The ion-laden water is applied to at least one graphene sheet perforated with apertures dimensioned to pass water molecules and to not pass the smallest relevant ion. The deionized water flowing through the perforated graphene sheet is collected. The ions which are not passed can be purged. In another embodiment, the ion-laden water is applied to a first graphene sheet perforated with apertures dimensioned to block chlorine ions and through a second graphene sheet perforated with apertures dimensioned to block sodium ions. The concentrated chlorine and sodium ions accumulating at the first and second perforated graphene sheets can be separately harvested.

Abstract: Articles containing a matrix material and plurality of copper nanoparticles in the matrix material that have been at least partially fused together are described. The copper nanoparticles are less than about 20 nm in size. Copper nanoparticles of this size become fused together at temperatures and pressures that are much lower than that of bulk copper. In general, the fusion temperatures decrease with increasing applied pressure and lowering of the size of the copper nanoparticles. The size of the copper nanoparticles can be varied by adjusting reaction conditions including, for example, surfactant systems, addition rates, and temperatures. Copper nanoparticles that have been at least partially fused together can form a thermally conductive percolation pathway in the matrix material.

Abstract: A separation arrangement isolates chlorine, sodium and possibly other ions from water. The ion-laden water is applied to at least one graphene sheet perforated with apertures dimensioned to pass water molecules and to not pass the smallest relevant ion. The deionized water flowing through the perforated graphene sheet is collected. The ions which are not passed can be purged. In another embodiment, the ion-laden water is applied to a first graphene sheet perforated with apertures dimensioned to block chlorine ions and through a second graphene sheet perforated with apertures dimensioned to block sodium ions. The concentrated chlorine and sodium ions accumulating at the first and second perforated graphene sheets can be separately harvested.