Abstract: Systems and methods described herein may produce a modified substrate. A process for producing a modified substrate may include providing a substrate that is 5 microns or less in thickness, ion tracking the substrate, and etching the tracked substrate with an etchant to produce a plurality of pores in the substrate. In some implementations, the substrate may be a polymer. In some implementations, the ion tracking may include controlling a flux of ions passing through the substrate to achieve a desired pore density. In some implementations, the track-etching of the substrate may create a 10% or more porosity in the substrate. In some implementations, the process may further include using the track-etched substrate as a support substrate for at least one of a single-layer graphene film, multi-layer graphene film, stack of graphene films, nanostructure of graphene flakes, or nanostructure of graphene platelets.

Abstract: Modified substrates are provided having nano- or microscale wells, tracks, channels, pores or perforations. Also provided are methods of making the same.

Abstract: Modified substrates are provided having nano- or microscale wells, tracks, channels, pores or perforations. Also provided are methods of making the same.

Abstract: Various systems and methods relating to two-dimensional materials such as graphene. A membrane include a cross-linked graphene platelet polymer that includes a plurality of cross-linked graphene platelets. The cross-linked graphene platelets include a graphene portion and a cross-linking portion. The cross-linking portion contains a 4 to 10 atom link. The cross-linked graphene platelet polymer is produced by reaction of an epoxide functionalized graphene platelet and a (meth)acrylate or (meth)acrylamide functionalized cross-linker.

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: Sheets of graphene-based material comprising single layer graphene and suitable for formation of a plurality of perforations in the single layer graphene are provided. In an aspect, the sheets of graphene-based material are formed by chemical vapor deposition followed by one or more conditioning steps. In a further aspect, the sheets of graphene-based material include non-graphenic carbon-based material and may be characterized the amount, mobility and/or volatility of the non-graphenic carbon-based material.

Abstract: A method for transferring a graphene sheet from a copper substrate to a functional substrate includes forming the graphene sheet on the copper substrate using chemical vapor deposition, and irradiating the graphene sheet disposed on the copper substrate with a plurality of xenon ions using broad beam irradiation to form a prepared graphene sheet. The prepared graphene sheet is resistant to forming unintentional defects induced during transfer of the prepared graphene sheet to the functional substrate. The method further includes removing the copper substrate from the prepared graphene sheet using an etchant bath, floating the prepared graphene sheet in a floating bath, submerging the functional substrate in the floating bath, and decreasing a fluid level of the floating bath to lower the prepared graphene sheet onto the functional substrate.

Abstract: Two-dimensional materials having apertures in their basal planes are described, where at least a portion of the apertures are occluded with a selectively introduced occluding moiety. Occluding moieties that pass into apertures function to occlude apertures. Composite membranes are described having a porous substrate with a two-dimensional material disposed on the membrane and covering only a portion of the pores, wherein at least a portion of uncovered substrate pores are occluded. Pore occlusion can be achieved by introduction of an occluding particle optionally followed by chemical reaction, deformation or swelling of the particle to facilitate occlusion of pores. Two-dimensional materials covering substrate pores can be size-selected and optionally functionalized providing for selective permeability through composite membranes. Methods for occluding defects and apertures in two-dimensional materials and for selectively occluding pores in composite membranes are provided.

Abstract: A method for transferring a graphene sheet from a copper substrate to a functional substrate includes forming the graphene sheet on the copper substrate using chemical vapor deposition, and irradiating the graphene sheet disposed on the copper substrate with a plurality of xenon ions using broad beam irradiation to form a prepared graphene sheet. The prepared graphene sheet is resistant to forming unintentional defects induced during transfer of the prepared graphene sheet to the functional substrate. The method further includes removing the copper substrate from the prepared graphene sheet using an etchant bath, floating the prepared graphene sheet in a floating bath, submerging the functional substrate in the floating bath, and decreasing a fluid level of the floating bath to lower the prepared graphene sheet onto the functional substrate.

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: Two-dimensional materials can be formed into enclosures for various substances and a substrate layer can be provided on an outside and/or on an inside of the enclosure, wherein the enclosure is not cytotoxic. The enclosures can be exposed to an environment, such as a biological environment (in vivo or in vitro), where the fibrous layer can promote vascular ingrowth. One or more substances within the enclosure can be released into the environment, one or more selected substances from the environment can enter the enclosure, one or more selected substances from the environment can be prevented from entering the enclosure, one or more selected substances can be retained within the enclosure, or combinations thereof. The enclosure can, for example, allow a sense-response paradigm to be realized. The enclosure can, for example, provide immunoisolation for materials, such as living cells, retained therein.

Abstract: Perforated sheets of graphene-based material having a plurality of perforations are provided. The perforated sheets may include perforated single layer graphene. The perforations may be located over greater than 10% of said area of said sheet of graphene-based material and the mean pore size of the perforations selected from the range of 0.3 nm to 1 ?m. Methods for making the perforated sheets are also provided.

Abstract: Sheets of graphene-based material comprising single layer graphene and suitable for formation of a plurality of perforations in the single layer graphene are provided. In an aspect, the sheets of graphene-based material are formed by chemical vapor deposition followed by one or more conditioning steps. In a further aspect, the sheets of graphene-based material include non-graphenic carbon-based material and may be characterized the amount, mobility and/or volatility of the non-graphenic carbon-based 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: Various systems and methods relating to two-dimensional materials such as graphene. A membrane include a cross-linked graphene platelet polymer that includes a plurality of cross-linked graphene platelets. The cross-linked graphene platelets include a graphene portion and a cross-linking portion. The cross-linking portion contains a 4 to 10 atom link. The cross-linked graphene platelet polymer is produced by reaction of an epoxide functionalized graphene platelet and a (meth)acrylate or (meth)acrylamide functionalized cross-linker.

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: 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 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: 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.