Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/56—After-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
  • B01D67/0081—After-treatment of organic or inorganic membranes
  • B01D67/0083—Thermal after-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
  • B01D67/0081—After-treatment of organic or inorganic membranes
  • B01D67/009—After-treatment of organic or inorganic membranes with wave-energy, particle-radiation or plasma
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
  • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
  • B01D69/06—Flat membranes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/02—Inorganic material
  • B01D71/021—Carbon
  • B01D71/0211—Graphene or derivates thereof
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/15—Nano-sized carbon materials
  • C01B32/182—Graphene
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/15—Nano-sized carbon materials
  • C01B32/182—Graphene
  • C01B32/194—After-treatment
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/26—Deposition of carbon only
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2323/00—Details relating to membrane preparation
  • B01D2323/34—Use of radiation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2323/00—Details relating to membrane preparation
  • B01D2323/34—Use of radiation
  • B01D2323/345—UV-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/02—Details relating to pores or porosity of the membranes
  • B01D2325/0283—Pore size
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/02—Details relating to pores or porosity of the membranes
  • B01D2325/0283—Pore size
  • B01D2325/02831—Pore size less than 1 nm

Definitions

• Some embodiments provide a sheet comprising single layer graphene, the sheet being suitable for formation of a plurality of perforations in the single layer graphene.
• the sheet may be a macroscale sheet with at least one lateral dimension of the sheet being greater than 1 mm, greater than 1 cm or greater than 3 cm.
• a sheet of graphene-based material comprising: a single layer of graphene having a surface and a non-graphenic carbon-based material provided on said single layer graphene.
• the single layer of graphene may comprise at least two surfaces and a non-graphenic carbon-based material provided on said single layer graphene; wherein greater than 10% and less than 80% of said surfaces of said single layer graphene may be covered by said non-graphenic carbon-based material.
• said non-graphenic carbon-based material may be characterized by substantially limited mobility.
• said non-graphenic carbon-based material may be substantially nonvolatile.
• the macroscale sheet may be suitable for formation of perforations through exposure of the sheet to ions. In some further embodiments, the macroscale sheet may be suitable for formation of perforations through exposure of the sheet to ultraviolet light and an oxygen containing gas such as air.
• the perforated sheets may have a variety of applications including, but not limited to, filtration applications.
• suspended macroscale sheets and methods for making macroscale sheets comprising single layer graphene are provided.
• the macroscale sheet may be a sheet of graphene-based material comprising single layer graphene.
• the sheet of graphene-based material comprises a sheet of single layer graphene, multilayer graphene, or a combination thereof.
• the sheet of graphene-based material may be formed by chemical vapor deposition (CVD) followed by at least one additional conditioning or treatment step.
• the conditioning step may be selected from thermal treatment, UV-oxygen treatment, ion beam treatment, or combinations thereof.
• thermal treatment may include heating to a temperature from 200 °C to 800 °C at a pressure of 10 '7 torr to atmospheric pressure for a time of 2 hours to 8 hours.
• UV-ozone treatment may involve exposure to light from 150 nm to 300 nm and intensity from 10 to 100 mW/cm 2 or 100 to 1000 mW/cm 2 at 6mm distance for a time from 60 to 600 seconds.
• UV-oxygen treatment may be performed at room temperature or at a temperature greater than room temperature.
• UV-oxygen treatment may be performed at atmospheric pressure (e.g. 1 atm) or under vacuum.
• ion beam treatment may involve exposure of the graphene-based material to ions having an ion energy is from 50 eV to 1000 eV (for pretreatment) and the fluence is from 3 x 10 10 ions/cm 2 to 8 x 10 11 ions/cm 2 or 3 x l010 ions/cm 2 to 8 x 1013 ions/cm 2 (for pretreatment).
• the source of ions may be collimated, such as a broad beam or flood source.
• the ions may be noble gas ions such as Xe +
• one or more conditioning steps may be performed while the graphene-based material is attached to a substrate, such as a growth substrate.
• the sheet of graphene-based material following chemical vapor deposition may comprise a single layer of graphene having at least two surfaces and non- graphenic carbon based material provided on said surfaces of the single layer graphene.
• the non-graphenic carbon based material may be located on one of the two surfaces or on both.
• additional graphenic carbon may also be present on the surface(s) of the single layer graphene.
• methods for conditioning sheets of graphene based material may reduce the extent to which the non-graphenic carbon based material covers the surface(s) of the single layer graphene, or reduce the mobility of said non-graphenic carbon based material, or reduce the volatility of said non-graphenic carbon based material, or combinations thereof.
• greater than 10% and less than 80%, greater than 20% and less than 80%, greater than 40% and less than 80%) or greater than 60% and less than 80% of the surface(s) of the single layer graphene may be covered by the non-graphenic carbon-based material following additional conditioning step(s).
• the graphene-based material may not be perforated after the conditioning step(s).
• the conditioning/treatment process may not substantially affect the domain size or extent of defects in the material.
• said single layer graphene before or after conditioning treatment may be characterized by an average size domain for long range order greater than or equal to 1 micrometer, long range lattice periodicity on the order of 1 micrometer and/or has an extent of disorder characterized by less than 1% content of lattice defects.
• the non-graphenic carbon-based material may comprise at least 50% carbon, from 10% carbon to 100% carbon or at or 20% to 100% carbon.
• said non-graphenic carbon-based material may further comprise non-carbon elements.
• said non-carbon elements may be selected from the group consisting of hydrogen, oxygen, silicon, copper, iron, aluminum, magnesium, calcium, boron, and nitrogen and combinations thereof.
• aluminum, magnesium, calcium, boron, and nitrogen are present only in trace amounts
• said non- graphenic carbon-based material may have an elemental composition comprising carbon, hydrogen and oxygen.
• said non-graphenic carbon-based material may have a molecular composition comprising amorphous carbon, one or more hydrocarbons, oxygen containing carbon compounds, nitrogen containing carbon compounds, or any combination of these.
• the non-carbon element such as boron or silicon substitutes for carbon in the lattice.
• said non-graphenic carbon-based material may not exhibit long range order.
• the non-graphenic carbon-based material may be in physical contact with at least one of said surfaces of said single layer graphene.
• the characteristics of the non-graphenic carbon material may be determined after at least one conditioning process.
• Some embodiments provide sheets of graphene-based material suspended over a supporting structure.
• CVD graphene or graphene-based material can be liberated from its growth substrate (e.g., Cu) and transferred to a supporting grid, mesh or other porous supporting structure.
• the porous supporting structure may be polymeric, metallic or ceramic.
• the supporting structure may be configured so that at least some portions of the sheet of graphene-based material are suspended from the supporting structure. For example, at least some portions of the sheet of graphene- based material may not be in contact with the supporting structure.
• the suspended area may be greater than 10 nm and less than 10 micrometers, and sometimes greater than 10 micrometers.
• a sheet of graphene-based material comprising: single layer graphene having at least two surfaces; and a non-graphenic carbon-based material provided on said single layer graphene; wherein greater than 10% and less than 80% of said surfaces of said single layer graphene may be covered by said non-graphenic carbon-based material; wherein exposure of said sheet of graphene-based material to ions characterized by an ion energy ranging from 10 eV to 100 keV and a fluence ranging from 1 xlO 13 ions/cm 2 to lxlO 21 ions/cm 2 may produce perforations in said sheet of graphene-based material.
• the single layer graphene may be suspended.
• a mask or template may not be present between the source of ions and the sheet of graphene-based material.
• the source of ions may be collimated, such as a broad beam or flood source.
• the ions may be noble gas ions selected from the group consisting of Xe+ ions, Ne+ ions, or Ar+ ions, or are helium ions.
• the ions may be selected from the group consisting of Xe+ ions, Ne+ ions, or Ar+ ions, wherein the ion energy ranges from 5 eV to 50 eV and the ion dose ranges from 5xl0 14 ions/cm 2 to 5xl0 Lj ions/cm 2 . In some embodiments, the ion energy ranges from 1 keV to 40 keV and the ion dose ranges from lxlO 15 ions/cm 2 to lxl0 2 : ions/cm 2 . These parameters can be used for He+ ions. In some embodiments, a background gas may be present during ion irradiation.
• the sheet of graphene-based material may be exposed to the ions in an environment comprising partial pressure of 5 X 10 '4 torr to 5 X 10 "5 torr of oxygen, nitrogen or carbon dioxide at a total pressure of 10 "3 torr to 10 "5 torr.
• the ion irradiation conditions when a background gas is present may include an ion energy ranging from 100 eV to 1000 eV and an ion dose ranging from 1 xlO 1 ' ions/cm 2 to lxlO 14 ions/cm 2 .
• a quasi-neutral plasma may be used under these conditions.
• a sheet of graphene-based material comprising: single layer graphene having at least two surfaces; and a non-graphenic carbon-based material provided on said single layer graphene; wherein greater than 10% and less than 80% of said surfaces of said single layer graphene may be covered by said non-graphenic carbon-based material; wherein exposure of said sheet of graphene-based material to ultraviolet radiation and an oxygen containing gas at an irradiation intensity from 10 to 100 mW/cm 2 for a time from 60 to 1200 sec may produce perforations in said sheet of graphene-based material.
• at least a portion of the single layer graphene is suspended.
• a mask or template may not be present between the source of ions and the sheet of graphene-based material.
• the macroscale sheet of graphene-based material may be suitable for formation of perforations over greater than 10% or greater or 15% or greater of said area of said sheet of graphene-based material.
• at least one lateral dimension of the sheet may be from 10 nm to 10 cm, or greater than 1 mm to less than or equal to 10 cm, or lateral dimensions as described herein.
• the mean of the pore size may be from 0.3 nm to 1 ⁇ .
• the coefficient of variation of the pore size may be from 0.1 to 2.
• perforated (hole) area may correspond to 0.1% or greater of said area of said sheet of graphene-based material.
• the perforations may be characterized by an average area of said perforations selected from the range of 0.2 nm 2 to 0.25 ⁇ 2 .
• FIG. 1 is a transmission electron microscope (TEM) image illustrating a graphene based material after conditioning treatment.
• FIG. 2 is another TEM image illustrating a graphene based material after conditioning treatment
• Graphene represents a form of carbon in which the carbon atoms reside within a single atomically thin sheet or a few layered sheets (e.g., about 20 or less) of fused six-membered rings forming an extended sp 2 -hybridized carbon planar lattice.
• Graphene-based materials include, but are not limited to, single layer graphene, multilayer graphene or interconnected single or multilayer graphene domains and combinations thereof.
• graphene-based materials also include materials which have been formed by stacking single or multilayer graphene sheets.
• multilayer graphene includes 2 to 20 layers, 2 to 10 layers or 2 to 5 layers.
• layers of multilayered graphene are stacked, but are less ordered in the z direction (perpendicular to the basal plane) than a thin graphite crystal.
• a sheet of graphene-based material is a sheet of single or multilayer graphene or a sheet comprising a plurality of interconnected single or multilayer graphene domains, which may be observed in any known manner such as using for example small angle electron diffraction, transmission electron microscopy, etc.
• the multilayer graphene domains have 2 to 5 layers or 2 to 10 layers.
• a domain refers to a region of a material where atoms are substantially uniformly ordered into a crystal lattice. A domain is uniform within its boundaries, but may be different from a neighboring region. For example, a single crystalline material has a single domain of ordered atoms.
• At least some of the graphene domains are nanocrystals, having domain size from 1 to 100 nm or 10-100 nm. In some embodiments, at least some of the graphene domains have a domain size greater than 100 nm to 1 micron, or from 200 nm to 800 nm, or from 300 nm to 500 nm. In some embodiments, a domain of multilayer graphene may overlap a neighboring domain. Grain boundaries formed by crystallographic defects at edges of each domain may differentiate between neighboring crystal lattices.
• a first crystal lattice may be rotated relative to a second crystal lattice, by rotation about an axis perpendicular to the plane of a sheet, such that the two lattices differ in crystal lattice orientations.
• the sheet of graphene-based material comprises a sheet of single or multilayer graphene or a combination thereof.
• the sheet of graphene- based material is a sheet of single or multilayer graphene or a combination thereof.
• the sheet of graphene-based material is a sheet comprising a plurality of interconnected single or multilayer graphene domains.
• the interconnected domains are covalently bonded together to form the sheet.
• the sheet is polycrystalline.
• said single layer graphene is characterized by an average size domain for long range order greater than or equal to ⁇ ⁇ .
• said single layer graphene has an extent of disorder characterized an average distance between crystallographic defects of lOOnm.
• the thickness of the sheet of graphene-based material is from 0.3 to 10 nm, 0.34 to 10 nm, from 0.34 to 5 nm, or from 0.34 to 3 nm. In some embodiments, the thickness includes both single layer graphene and the non-graphenic carbon.
• a sheet of graphene-based material comprises intrinsic or native defects.
• Intrinsic or native defects may result from preparation of the graphene-based material in contrast to perforations which are selectively introduced into a sheet of graphene-based material or a sheet of graphene.
• Such intrinsic or native defects may include, but are not limited to, lattice anomalies, pores, tears, cracks or wrinkles.
• Lattice anomalies can include, but are not limited to, carbon rings with other than 6 members (e.g.
• graphene is the dominant material in a graphene-based material.
• a graphene-based material may comprise at least 20% graphene, 30% graphene, or at least 40% graphene, or at least 50% graphene, or at least 60% graphene, or at least 70% graphene, or at least 80% graphene, or at least 90% graphene, or at least 95% graphene.
• a graphene-based material comprises a range of graphene selected from 30% to 95%, or from 40% to 80% from 50% to 70%, from 60% to 95% or from 75% to 100%.
• the amount of graphene in the graphene-based material is measured as an atomic percentage utilizing known methods including transmission electron microscope examination, or alternatively if TEM is ineffective another similar measurement technique.
• a sheet of graphene-based material further comprises non- graphenic carbon-based material located on at least one surface of the sheet of graphene-based material.
• the sheet is exemplified by two base surfaces (e.g. top and bottom faces of the sheet, opposing faces) and side faces.
• the "bottom" face of the sheet is that face which contacted the substrate during CVD growth of the sheet and the "free" face of the sheet opposite the "bottom” face.
• non-graphenic carbon-based material may be located on one or both base surfaces of the sheet (e.g. the substrate side of the sheet and/or the free surface of the sheet).
• the sheet of graphene-based material includes a small amount of one or more other materials on the surface, such as, but not limited to, one or more dust particles or similar contaminants.
• the amount of non-graphenic carbon-based material is less than the amount of graphene. In some further embodiments, the amount of non-graphenic carbon material is three to five times the amount of graphene; this may be measured in terms of mass. In some additional embodiments, the non-graphenic carbon material is characterized by a percentage by mass of said graphene-based material selected from the range of 0% to 80% In some embodiments, the surface coverage of the sheet by non-graphenic carbon-based material is greater than zero and less than 80%, from 5% to 80%, from 10% to 80%, from 5% to 50% or from 10% to 50%. This surface coverage may be measured with transmission electron microscopy, which gives a projection.
• the amount of graphene in the graphene-based material is from 60% to 95% or from 75% to 100%.
• the amount of graphene in the graphene-based material is measured as mass percentage utilizing known methods preferentially using transmission electron microscope examination, or alternatively if TEM is ineffective using other similar techniques
• the layer comprising the sheet of graphene-based material further comprises non-graphenic carbon-based material located on the surface of the sheet of graphene-based material.
• the non-graphenic carbon-based material does not possess long range order and may be classified as amorphous.
• the non-graphenic carbon-based material further comprises elements other than carbon and/or hydrocarbons.
• non-carbon elements which may be incorporated in the non-graphenic carbon include hydrogen, oxygen, silicon, copper, and iron.
• the non-graphenic carbon-based material comprises hydrocarbons.
• carbon is the dominant material in non-graphenic carbon-based material.
• a non-graphenic carbon-based material in some embodiments comprises at least 30% carbon, or at least 40% carbon, or at least 50% carbon, or at least 60% carbon, or at least 70% carbon, or at least 80% carbon, or at least 90% carbon, or at least 95% carbon.
• a non-graphenic carbon-based material comprises a range of carbon selected from 30% to 95%, or from 40% to 80%, or from 50% to 70%.
• the amount of carbon in the non- graphenic carbon-based material is measured as an atomic percentage utilizing known methods preferentially using transmission electron microscope examination, or alternatively if TEM is ineffective, using other similar techniques.
• the surface mobility of the non-graphenic carbon-based material is such that, when irradiated with the perforation parameters described in this application, the non-graphenic carbon-based material has a surface mobility such that the perforation process results ultimately in perforation.
• hole formation is believed to related to beam induced carbon removal from the graphene sheet and thermal replenishment of carbon in the hole region by non graphenic carbon. The replenishment process is dependent upon energy entering the system during perforation and the resulting surface mobility of the non-graphenic carbon based material.
• the rate of graphene removal is higher than the non-graphenic carbon hole filling rate. These competing rates depend on the non-graphenic carbon flux (mobility [viscosity and temperature] and quantity) and the graphene removal rate (particle mass, energy, flux).
• the volatility of the non-graphenic carbon-based material is less than that which is obtained by heating the sheet of graphene-based material to 500°C for 4 hours in vacuum or at atmospheric pressure with an inert gas.
• Perforation techniques suitable for use in perforating the graphene-based may include ion-based perforation methods and UV-oxygen based methods.
• Ion-based perforation methods include methods in which the graphene-based material is irradiated with a directional source of ions.
• the ion source is collimated.
• the ion source is a broad beam or flood source.
• a broad field or flood ion source can provide an ion flux which is significantly reduced compared to a focused ion beam.
• the ion source inducing perforation of the graphene or other two- dimensional material is considered to provide a broad ion field, also commonly referred to as an ion flood source.
• the ion flood source does not include focusing lenses.
• the ion source is operated at less than atmospheric pressure, such as at 10 ' to 10 "5 torr or 10 "4 to 10 "6 torr.
• the environment also contains background amounts (e.g. on the order of 10 "5 torr) of oxygen (O2), nitrogen (N2) or carbon dioxide (CO 2 ).
• the ion beam may be perpendicular to the surface of the layer(s) of the material (incidence angle of 0 degrees) or the incidence angle may be from 0 to 45 degrees, 0 to 20 degrees, 0 to 15 degrees or 0 to 10 degrees.
• exposure to ions does not include exposure to plasma.
• UV-oxygen based perforation methods include methods in which the graphene-based material is simultaneously exposed to ultraviolet (UV) light and an oxygen containing gas.
• Ozone may be generated by exposure of an oxygen containing gas such as oxygen or air to the UV light, in which case the graphene-based material is exposed to oxygen.
• Ozone may also be supplied by an ozone generator device.
• the UV-ozone based perforation method further includes exposure of the graphene-based material to atomic oxygen. Suitable wavelengths of UV light include, but are not limited to wavelengths below 300 nm or from 150 nm to 300 nm.
• the intensity from 10 to 100 mW/cm 2 at 6mm distance or 100 to 1000 mW/cm 2 at 6mm distance.
• suitable light is emitted by mercury discharge lamps (e.g. about 185 nm and 254 nm).
• UV/ozone cleaning is performed at room temperature or at a temperature greater than room temperature. In some further embodiments, UV/ozone cleaning is performed at atmospheric pressure (e.g. 1 atm) or under vacuum.
• Perforations are sized as described herein to provide desired selective permeability of a species (atom, molecule, protein, virus, cell, etc.) for a given application.
• Selective permeability relates to the propensity of a porous material or a perforated two-dimensional material to allow passage (or transport) of one or more species more readily or faster than other species.
• Selective permeability allows separation of species which exhibit different passage or transport rates.
• selective permeability correlates to the dimension or size (e.g., diameter) of apertures and the relative effective size of the species.
• Selective permeability of the perforations in two-dimensional materials such as graphene-based materials can also depend on functionalization of perforations (if any) and the specific species.
• the characteristic size of the perforation is from 0.3 to 10 nm, from 1 to 10 nm, from 5 to 10 nm, from 5 to 20 nm, from 10 nm to 50 nm, from 50 nm to 100 nm, from 50 nm to 150 nm, from 100 nm to 200 nm, or from 100 nm to 500 nm.
• the average pore size is within the specified range. In some embodiments, 70% to 99%, 80% to 99%, 85% to 99% or 90 to 99% of the perforations in a sheet or layer fall within a specified range, but other pores fall outside the specified range.
• Nanomaterials in which pores are intentionally created may be referred to as perforated graphene, perforated graphene-based materials, perforated two-dimensional materials, and the like.
• Perforated graphene-based materials include materials in which non-carbon atoms have been incorporated at the edges of the pores.
• Pore features and other material features may be characterized in a variety of manners including in relation to size, area, domains, periodicity, coefficient of variation, etc. For instance, the size of a pore may be assessed through quantitative image analysis utilizing images preferentially obtained through transmission electron microscopy, and if TEM is ineffective, through scanning electron microscopy and the like, as for example presented in Figs. 1 and 2.
• the boundary of the presence and absence of material identifies the contour of a pore.
• the size of a pore may be determined by shape fitting of an expected species against the imaged pore contour where the size measurement is characterized by smallest dimension unless otherwise specified.
• the shape may be round or oval.
• the round shape exhibits a constant and smallest dimension equal to its diameter.
• the width of an oval is its smallest dimension. The diameter and width measurements of the shape fitting in these instances provide the size measurement, unless specified otherwise.
• Each pore size of a test sample may be measured to determine a distribution of pore sizes within the test sample Other parameters may also be measured such as area, domain, periodicity, coefficient of variation, etc.
• Multiple test samples may be taken of a larger membrane to determine that the consistency of the results properly characterizes the whole membrane. In such instance, the results may be confirmed by testing the performance of the membrane with test species. For example, if measurements indicate that certain sizes of species should be restrained from transport across the membrane, a performance test provides verification with test species. Alternatively, the performance test may be utilized as an indicator that the pore measurements will determine a concordant pore size, area, domains, periodicity, coefficient of variation, etc.
• the perforations are characterized by a distribution of pores with a dispersion characterized by a coefficient of variation of 0.1 to 2.
• the size distribution of holes may be narrow, e.g., limited to a coefficient of variation less than 2.
• the characteristic dimension of the holes is selected for the application.
• the coefficient of variation of the pore size may be calculated herein as the ratio of the standard deviation of the pore size to the mean of the pore size as measured across the test samples.
• the average area of perforations is an averaged measured area of the pores as measured across the test samples.
• the ratio of the area of the perforations to the ratio of the area of the sheet may be used to characterize the sheet as a density of perforations.
• the area of a test sample may be taken as the planar area spanned by the test sample. Additional sheet surface area may be excluded due to wrinkles other non-planar features. Characterization may be based on the ratio of the area of the perforations to the test sample area as density of perforations excluding features such as surface debris. Characterization may be based on the ratio of the area of the perforations to the suspended area of the sheet.
• multiple test samples may be taken to confirm consistency across tests and verification may be obtained by performance testing.
• the density of perforations may be, for example, 2 per nm 2 (21 nm 2 to 1 per ⁇ 2 (1/ ⁇ 2 ).
• the perforated area comprises 0.1% or greater, 1% or greater or 5% or greater of the sheet area, less than 10% of the sheet area, less than 15% of the sheet area, from 0. 1% to 15% of the sheet area, from 1% to 15% of the sheet area, from 5% to 15% of the sheet area or from 1% to 10% of the sheet area.
• the perforations are located over greater than 10% or greater than 15% of said area of said sheet of graphene- based material.
• a macroscale sheet is macroscopic and observable by the naked eye.
• at least one lateral dimension of the sheet is greater than 1 cm, greater than 1 mm or greater than 5 mm.
• the sheet is larger than a graphene flake which would be obtained by exfoliation of graphite in known processes used to make graphene flakes.
• the sheet has a lateral dimension greater than about 1 micrometer.
• the lateral dimension of the sheet is less than 10 cm.
• the sheet has a lateral dimension (e.g., perpendicular to the thickness of the sheet) greater than 1 mm and less than 10 cm.
• Chemical vapor deposition growth of graphene-based material typically involves use of a carbon containing precursor material, such as methane and a growth substrate.
• the growth substrate is a metal growth substrate.
• the metal growth substrate is a substantially continuous layer of metal rather than a grid or mesh.
• Metal growth substrates compatible with growth of graphene and graphene-based materials include transition metals and their alloys.
• the metal growth substrate is copper based or nickel based.
• the metal growth substrate is copper or nickel.
• the graphene-based material is removed from the growth substrate by dissolution of the growth substrate.
• FIG. 1 is a transmission electron microscope image illustrating a graphene based material after conditioning treatment.
• FIG. 2 is another transmission electron microscope image showing a graphene based material after conditioning treatment.
• the graphene based material was synthesized using chemical vapor deposition. After synthesis, the material was exposed to an ion beam while on the copper growth substrate; the ions were Xe ions at 500V at 80°C with a fluence of 1.25 x 10 13 ions/cm 2 . Then the graphene based material was transferred to a TEM grid and while suspended received 120 seconds of treatment at atmospheric pressure with atmospheric gas with Ultra- VioletUV parameters as described herein. The graphene based material was baked at 160 °C for about 6 hours before imaging. In FIG. 1 and FIG. 2, label 10 indicates single layer graphite regions while label 20 indicates largely non-graphitic carbon based material.

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• 2016
  • 2016-04-14 EP EP16833431.6A patent/EP3331816A4/de not_active Withdrawn
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