WO2021170244A1 - Membrane and method of manufacture thereof - Google Patents

Membrane and method of manufacture thereof Download PDF

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Publication number
WO2021170244A1
WO2021170244A1 PCT/EP2020/055209 EP2020055209W WO2021170244A1 WO 2021170244 A1 WO2021170244 A1 WO 2021170244A1 EP 2020055209 W EP2020055209 W EP 2020055209W WO 2021170244 A1 WO2021170244 A1 WO 2021170244A1
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Prior art keywords
amorphous carbon
amphiphilic
monomers
containing monomers
carbon membrane
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PCT/EP2020/055209
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French (fr)
Inventor
Xue Liu
Grégory F SCHNEIDER
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Universiteit Leiden
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Priority to PCT/EP2020/055209 priority Critical patent/WO2021170244A1/en
Publication of WO2021170244A1 publication Critical patent/WO2021170244A1/en

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    • 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
    • B01D67/0002—Organic membrane manufacture
    • B01D67/0006—Organic membrane manufacture by chemical reactions
    • 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
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • B01D69/122—Separate manufacturing of ultra-thin membranes
    • 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
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • B01D69/125—In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
    • 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
    • B01D71/06—Organic material
    • B01D71/44—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of groups B01D71/26-B01D71/42
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/30—Cross-linking
    • 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
    • B01D2325/04—Characteristic thickness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/38—Hydrophobic membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/39—Amphiphilic membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/422—Electrodialysis

Definitions

  • This invention relates to an amorphous carbon membrane and a method of fabricating an amorphous carbon membrane.
  • a method of fabricating an atomically or molecularly thin amorphous carbon membrane including the steps of: providing amphiphilic or hydrophobic carbon-containing monomers on a liquid surface; packing the amphiphilic or hydrophobic carbon-containing monomers; and causing polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers to form the amorphous carbon membrane.
  • the method of the invention facilitates the assembly of an atomically or molecularly thin amorphous carbon membrane using a bottom-up approach that is not only compatible with the requirement to produce an atomic or molecular thickness but also readily adapted to tune the properties of the resultant amorphous carbon membrane with excellent reproducibility.
  • the versatility of the method of the invention enables the creation of an atomically or molecularly thin amorphous carbon membrane with tunable properties for use in a wide range of applications and devices.
  • the method enables the manufacture of an atomically or molecularly thin amorphous carbon membrane with a controllable thickness, e.g. through selection of a suitable type of monomer and/or packing conditions and/or polymerisation conditions. Hence, a consistent thickness throughout the amorphous carbon membrane can be provided, thus facilitating large-area fabrication of an atomically or molecularly thin amorphous carbon membrane.
  • the amorphous carbon membrane may have a nanometre-scale thickness or a sub-nanometre-scale thickness.
  • the thickness of the amorphous carbon membrane may be from 0.3 nm to 3.0 nm or may correspond to any 0.01 nm interval in the range of 0.3 nm and 3.0 nm.
  • the method may include the step of forming pores during the formation of the amorphous carbon membrane, wherein each pore is a nanopore or a sub-nanopore. In such embodiments, a width of each pore is from 0.01 nm to 100 nm.
  • the pores of the resultant amorphous carbon membrane consist of pores with widths from 0.01 nm to 100 nm, that is to say the resultant amorphous carbon membrane does not include one or more pores with a width outside the range of 0.01 nm to 100 nm.
  • One or more pores may have a width corresponding to any 0.01 nm interval in the range of 0.01 nm and 100 nm.
  • the method of the invention enables the creation of natural nanopores and/or sub nanopores during the synthesis of the amorphous carbon membrane and thus allows the fabrication of an atomically or molecularly thin amorphous carbon membrane with nanoporosity and/or sub-nanoporosity in its pristine state, without requiring additional steps to artificially introduce nanopores and/or sub- nanopores into the amorphous carbon membrane.
  • This in turn is conducive to large-area fabrication of atomically or molecularly thin amorphous carbon membranes with nano-porosity and/or sub-nanoporosity.
  • the method of the invention enables tuning of the size of each pore, e.g. through selection of a suitable type of monomer and/or packing conditions and/or polymerisation conditions, in order to obtain a desired level of porosity resolution.
  • the method of the invention therefore obviates the need for creating artificial nanopores and/or sub- nanopores in the amorphous carbon membrane post-formation using transmission electron microscope (TEM) sputtering or lithographic techniques, both of which due to slow processing speeds and high cost are not suitable for large-area fabrication of atomically or molecularly thin amorphous carbon membranes with nanoporosity and/or sub-nanoporosity.
  • TEM transmission electron microscope
  • the method may include the step of aligning or orienting the amphiphilic or hydrophobic carbon-containing monomers on the liquid surface prior to their packing.
  • the step of packing the amphiphilic or hydrophobic carbon-containing monomers may include using at least one barrier to compress the amphiphilic or hydrophobic carbon-containing monomers.
  • the or each barrier may be manually operated or automatically operated in order to provide precise control over the packing of the amphiphilic or hydrophobic carbon-containing monomers.
  • the method of the invention may include the step of providing a precursor source that contains the amphiphilic or hydrophobic carbon-containing monomers. This provides a reliable means of providing the amphiphilic or hydrophobic carbon-containing monomers on the liquid surface.
  • the precursor source may be a solution that contains the amphiphilic or hydrophobic carbon-containing monomers.
  • the choice of monomers depends on the desired properties of the resultant amorphous carbon membrane.
  • the amphiphilic or hydrophobic carbon-containing monomers may be hexa(2,2'-dipyridylamino)hexabenzocoronene (HPAHBC) monomers, hexa(2,2':6',2"- terpyridin-4'-yl)phenylbenzene (TRY) monomers or hexa(4-methylphenyl)benzene (HMPB) monomers.
  • the amphiphilic or hydrophobic carbon-containing monomers may be polyaromatic monomers or polycyclic aromatic hydrocarbons.
  • each polyaromatic monomer includes a polyaromatic core moiety and a functionalised rim moiety connected to and surrounding the polyaromatic core moiety.
  • Polymerisation between at least some of the packed amphiphilic or hydrophobic carbon- containing monomers may take place via a wide range of reaction mechanisms depending on the chemical structures of the amphiphilic or hydrophobic carbon-containing monomers.
  • the polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers may include crosslinking of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers.
  • the crosslinking of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers includes thermal annealing of the packed amphiphilic or hydrophobic carbon- containing monomers.
  • the amorphous carbon membrane may be freestanding.
  • the method may include the step of transferring the packed amphiphilic or hydrophobic carbon-containing monomers from the liquid surface to a target substrate before the polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers to form the amorphous carbon membrane.
  • Transferring the packed amphiphilic or hydrophobic carbon-containing monomers to the target substrate facilitates the polymerisation of the packed amphiphilic or hydrophobic carbon-containing monomers and the post-processing of the amorphous carbon membrane for use in an application or a device, e.g. by transporting the packed amphiphilic or hydrophobic carbon-containing monomers to a new location to carry out their polymerisation and/or by using the target substrate as a support structure for the amorphous carbon membrane during the post-processing and/or in the application or device.
  • an atomically or molecularly thin amorphous carbon membrane comprising polymerised amphiphilic or hydrophobic carbon-containing monomers.
  • the amorphous carbon membrane may have a nanometre-scale thickness or a sub- nanometre-scale thickness.
  • the thickness of the amorphous carbon membrane may be from 0.3 nm to 3.0 nm or may correspond to any 0.01 nm interval in the range of 0.3 nm and 3.0 nm.
  • the amorphous carbon membrane may include natural nanopores.
  • a width of each nanopore may be from 0.01 nm to 100 nm.
  • the nanopores of the resultant amorphous carbon membrane consist of nanopores with widths from 0.01 nm to 100 nm, that is to say the resultant amorphous carbon membrane does not include one or more nanopores with a width outside the range of 0.01 nm to 100 nm.
  • One or more nanopores may have a width corresponding to any 0.01 nm interval in the range of 0.01 nm and 100 nm.
  • amphiphilic or hydrophobic carbon-containing monomers may be HPAHBC monomers, TPY monomers or HMPB monomers.
  • amphiphilic or hydrophobic carbon-containing monomers may be polyaromatic monomers or polycyclic aromatic hydrocarbons.
  • each polyaromatic monomer includes a polyaromatic core moiety and a functionalised rim moiety connected to and surrounding the polyaromatic core moiety.
  • the polymerised amphiphilic or hydrophobic carbon-containing monomers may be cross- linked.
  • the polymerised amphiphilic or hydrophobic carbon-containing monomers are cross-linked and thermally annealed.
  • the amorphous carbon membrane may be freestanding.
  • an atomically or molecularly thin amorphous carbon membrane obtainable through any one of the method of the first aspect of the invention and its embodiments described hereinabove.
  • the amorphous carbon membrane of the invention may be used in a wide range of applications.
  • a device comprising an atomically or molecularly thin amorphous carbon membrane according to any one of the amorphous carbon membranes of the second and third aspects of the invention and their embodiments described hereinabove, wherein the device is any one of:
  • a filter e.g. a water filter
  • a sequencing apparatus e.g. a sequencing apparatus for DNA or protein or sugar or polymer or biopolymer sequencing
  • a desalination apparatus e.g. a water desalination apparatus
  • a purification apparatus e.g. a water purification apparatus
  • an energy generation apparatus e.g. a fuel cell such as a direct methanol fuel cell
  • ⁇ an energy storage apparatus e.g. a fuel cell such as a direct methanol fuel cell
  • a support structure for a transmission electron microscopy (TEM) sample e.g. a TEM support grid
  • an electrodialysis apparatus such as a reverse electrodialysis apparatus.
  • Figure 1 shows a method of fabricating an amorphous carbon membrane according to an embodiment of the invention
  • Figures 2a and 2b show exemplary monomers for use in the method of Figure 1;
  • Figure 3 shows a photograph of an amorphous carbon membrane sample prepared using the method of Figure 1;
  • Figure 4 shows optical images of amorphous carbon membranes prepared using the method of Figure 1;
  • Figure 5 shows Raman spectra of monolayer amorphous carbon membranes prepared using the method of Figure 1;
  • Figures 6 and 7 shows 2D Raman mapping of amorphous carbon membranes prepared using the method of Figure 1;
  • Figures 8 and 9 show atomic force microscopy (AFM) images of amorphous carbon membranes prepared using the method of Figure 1 ;
  • Figure 10 shows a high resolution TEM image of an amorphous carbon membrane prepared using the method of Figure 1;
  • Figure 11 shows a scanning electron microscopy (SEM) image of an amorphous carbon membrane prepared using the method of Figure 1;
  • Figure 12 shows a reverse electrodialysis setup incorporating an amorphous carbon membrane prepared using the method of Figure 1;
  • FIGS 13 and 14 illustrate the characteristics of the reverse electrodialysis setup.
  • HPAHC monomers 10 may be replaced by TPY monomers, HMPB monomers, other polyaromatic monomers (preferably with a polyaromatic core moiety and a functionalised rim moiety connected to and surrounding the polyaromatic core moiety), polycyclic aromatic hydrocarbons or other amphiphilic or hydrophobic monomers.
  • a trough 12 is filled with water.
  • a solution 14 of a predetermined amount of chloroform solution containing HPAHBC monomers 10 is introduced drop-wise into a region of the water that is located between two barriers 16.
  • the chloroform solution then evaporates, leaving the HPAHBC monomers 10 to cover the available area on the water surface.
  • the pair of barriers 16 are then brought together to compress the monolayer to a specific surface pressure (e.g. 3 mN nr 1 , 10 mN nr 1 , 20 mN nr 1 and 30 mN nr 1 ) to increase the packing density of the HPAHBC monomers 10, which self-assemble on the water surface to form a dense monolayer of HPAHBC monomers 10.
  • a Langmuir film in the form of a monolayer of HPAHBC monomers 10 that are arranged and aligned on the air- water interface.
  • the alignment of the HPAHBC monomers 10 and the formation of the monolayer of HPAHBC monomers 10 on the water surface are due to the amphiphilic nature of the HPAHBC monomers 10.
  • the water in the trough 12 may be replaced by a different liquid and/or the trough 12 may be immersed in a different liquid or a gas so as to create a different gas-liquid or liquid-liquid interface.
  • the barriers 16 may be manually operated or automatically operated, e.g. using a computer-controlled actuator.
  • a flat solid copper substrate is brought into proximity with the monolayer of HPAHBC monomers 10 so as to permit horizontal deposition of the monolayer of HPAHBC monomers 10 onto a surface of the copper substrate.
  • the Langmuir-Schaefer film of HPAHBC monomers 10 is then subjected to conditions that are suitable for crosslinking the HPAHBC monomers 10 in a polymerisation step to form an amorphous carbon membrane 18.
  • the Langmuir-Schaefer film of HPAHBC monomers 10 is thermally annealed in an oven at 550°C or higher under vacuum (e.g. 1 mbar, Argon atmosphere) for 15-20 minutes to form the crosslinked amorphous carbon membrane 18.
  • the solid substrate may be oriented and dipped into the water to permit vertical deposition of a film of HPAHBC monomers.
  • the film of HPAHBC monomers on the solid substrate is referred to as a Langmuir-Blodgett film.
  • the atomically thin amorphous carbon membrane has a sub-nanometre-scale thickness.
  • the molecularly thin amorphous carbon membrane has a nanometre-scale thickness or a sub-nanometre-scale thickness.
  • the thickness of the amorphous carbon membrane may be from 0.3 nm to 3.0 nm or may correspond to any 0.01 nm interval in the range of 0.3 nm and 3.0 nm.
  • the amorphous carbon membrane comprises pores having a narrow size distribution in the range of 0.01 nm to 100 nm, where one or more pores may have a width corresponding to any 0.01 nm interval in the range of 0.01 nm and 100 nm.
  • the method of Figure 1 may be adapted to tune the thickness and pore size of the amorphous carbon membrane.
  • the thickness and pore size of the amorphous carbon membrane may be controlled by selecting a suitable type of amphiphilic or hydrophobic monomer.
  • the amphiphilic or hydrophobic carbon-containing monomers with different functional groups may be chosen in order to vary the thickness and nanopore size of the amorphous carbon membrane.
  • the thickness of the amorphous carbon membrane can be tuned by choosing different monomers.
  • HPAHBC monomers have a strong tt-p stacking effect and have a tendency to stand vertically on the water surface, thus resulting in an amorphous carbon membrane thickness of 2 nm that is close to the size of a HPAHBC monomer.
  • TPY monomers have a weak tt-p stacking effect due to the non-conjugated structure and have a tendency to stay flat on the water surface, with the maximum number of hydrogen bonds formed between pyridine and water, thus resulting in an amorphous carbon membrane thickness of 0.35 nm that is the thickness of a TRY molecule.
  • HMPB monomers have a weak tt-p stacking effect but have a tendency to tilt on the water surface and are not as well aligned on the water surface due to their hydrophobic nature, thus resulting in an amorphous carbon membrane thickness of 0.8-0.9 nm.
  • the pore size of the amorphous carbon membrane can be tuned by choosing different monomers.
  • the amphiphilic nature of HPAHBC monomers results in excellent alignment of the HPAHBC monomers on the water surface, thus resulting in small pores following the packing and polymerisation steps.
  • the hydrophobic HMPB monomers do not align as well as the HPAHBC monomers on the water surface, thus resulting in comparatively larger pores following the packing and polymerisation steps.
  • the compression speed and/or the degree of compression of the monolayer may be controlled to affect the packing of the monomers and thereby influence the subsequent polymerisation of the monomers, which in turn influences the atomic/molecular thickness of the amorphous carbon membrane.
  • the thermal annealing conditions influence the atomic/molecular thickness of the amorphous carbon membrane.
  • the method of Figure 1 therefore not only permits control over the magnitude and consistency of the thickness of the amorphous carbon membrane so as to fabricate an atomically or molecularly thin amorphous carbon membrane but also enables the creation of natural nanopores and/or sub-nanopores during the synthesis of the amorphous carbon membrane and thus allows the fabrication of an atomically or molecularly thin amorphous carbon membrane with nanoporosity and/or sub-nanoporosity in its pristine state.
  • the method of Figure 1 therefore facilitates the large-area assembly of an atomically or molecularly thin amorphous carbon membrane (e.g. at least a few square centimetres or larger) using a reproducible bottom-up approach.
  • FIG. 1 shows the chemical structures of the HPAHBC monomers, TPY monomers and HMPB monomers.
  • Figure 2b illustrates a non-limiting exemplary synthesis route for the HPAHBC monomers, each of which consists of six flexible dipyridylamino groups as the rim and one hexabenzocoronene (HBC) rigid core.
  • HBC hexabenzocoronene
  • TYP monomers and HMPB monomers are known in the art.
  • Figure 3 is a photograph of an amorphous carbon membrane prepared from TPY monomers and transferred to a silicon wafer. Despite the atomic or molecular thinness of the amorphous carbon membrane as indicated by its near-invisibility in the photograph, the amorphous carbon membrane has a comparatively large area of about 3.5 by 2.0 cm 2 .
  • Figure 4 shows optical images of sections of amorphous carbon membranes prepared from HPAHBC monomers (left image) and TPY monomers (right image), showing the ability of the method of Figure 1 to produce large area amorphous carbon membranes with atomic or molecular thinness indicated by their near-invisibility in the optical images.
  • Figure 5 shows Raman spectra of monolayer amorphous carbon membranes prepared from HPAHBC monomers (left image), TPY monomers (middle image) and HMPB monomers (right image). It can be seen from the left image of Figure 5 that the amorphous carbon membrane consists of the HPAHBC monomers by virtue of their almost identical Raman signals. No signal was observed for the TPY monomers and HMPB monomers due to their less conjugated chemical structures.
  • Figure 6 shows a 2D Raman mapping over a scan area of 50 pm by 50 pm of an amorphous carbon membrane prepared from TPY monomers, including a histogram of intensity ratio between D and G peaks. A Gaussian fitting curve is applied to the histogram. The intensity ratio between the D and G peaks is around 2.14 over the whole scan area, with a standard deviation of 6.9%. This indicates that the resultant amorphous carbon membrane exhibits relatively uniform thickness over the scan area.
  • Figure 7 shows a 2D Raman mapping over a scan area of 50 pm by 50 pm of an amorphous carbon membrane prepared from HMPB monomers.
  • a Gaussian fitting curve is applied to the histogram.
  • the intensity ratio between the D and G peaks is around 1.70 over the whole scan area, with a standard deviation of 7.1 %. This indicates that the resultant amorphous carbon membrane exhibits relatively uniform thickness over the scan area.
  • Figure 8 shows AFM images of amorphous carbon membranes prepared from HPAHBC monomers (left image), TPY monomers (middle image) and HMPB monomers (right image).
  • the thickness of the HPAHBC monomer-based amorphous carbon membrane is about 2.0 nm.
  • the thickness of the TPY monomer-based amorphous carbon membrane is about 0.36 nm.
  • the thickness of the HMPB monomer-based amorphous carbon membrane is about 0.80 nm. This shows the ability of the method of Figure 1 to tune the atomic or molecular thinness of the amorphous carbon membrane through the selection of a suitable monomer.
  • Figure 9 shows AFM images, at different magnifications, of an amorphous carbon membrane prepared from HMPB monomers. It can be seen from Figure 9 that natural nanopores in the range of 10 nm to 100 nm are formed in the amorphous carbon membrane using the method of Figure 1.
  • Figure 10 shows a high resolution TEM image of an amorphous carbon membrane prepared from HPAHBC monomers.
  • the histogram in Figure 10 shows that a substantial percentage of natural nanopores of about 3.6 nm in diameter or less are formed in the amorphous carbon membrane using the method of Figure 1.
  • Figure 11 shows an SEM image of an amorphous carbon membrane prepared from HPAHBC monomers and transferred to a solid substrate with 2 pm wide holes.
  • the scale bar in the SEM image is 4 pm long. It can be seen from Figure 11 that the amorphous carbon membrane is mechanically strong enough to be freestanding over the 2 pm wide holes.
  • the versatility of the method of Figure 1 enables the creation of a 2D amorphous carbon membrane with nanometre-scale and/or sub-nanometre-scale pore structures, the properties of which can be readily tuned to suit the requirements of a wide range of applications and devices. Particularly, the properties of the nanopores and/or subnanopores can be tuned to define proton, ion and/or small molecular selective nanopore and/or sub-nanopore structures.
  • Figure 12 shows a reverse electrodialysis apparatus incorporating an HPAHBC monomer- based amorphous carbon membrane 22 that is prepared using the method of Figure 1 and is cation selective with a selectivity of about 40%.
  • the HPAHBC monomer-based amorphous carbon membrane 22 is arranged in a KCI solution gradient. A voltage is applied across the KCI solution and membrane arrangement using Ag/AgCI electrodes 24 connected to the arrangement via respective salt bridges 26.
  • Figure 13 illustrates, in graph form, the variation in short-circuit current and open-circuit potential as a function of salt concentration gradient.
  • the short-circuit current and open- circuit potential are commonly measured quantities for assessing the performance of a reverse electrodialysis apparatus. It can be seen from Figure 13 that the HPAHBC monomer-based amorphous carbon membrane prepared using the method of Figure 1 can be used as an ion- selective membrane to directly generate electricity in the reverse electrodialysis apparatus.
  • Figure 14 illustrates, in graph form, the variation in current density and the corresponding output power density of the reverse electrodialysis apparatus as a function of the load resistance. It can be seen from Figure 14 that the use of the HPAHBC monomer-based amorphous carbon membrane in the reverse electrodialysis apparatus produces a high- short circuit current with a maximum output power density of 67 W/m 2 , which is about two orders of magnitude higher than the output power density produced by reverse electrodialysis apparatus using conventional polymer membranes.
  • the atomically or molecularly thin amorphous carbon membranes of the invention may be used in a range of other applications and devices, some non-limiting examples of which are described as follows.
  • the atomically or molecularly thin amorphous carbon membrane may be used to select and/or separate molecules from a retentate, where the molecules are able to permeate the nanopores of the amorphous carbon membrane based on the charge, size and shape of the molecules.
  • the separation of molecules may be performed in any one of: a direct methanol fuel cell; a DNA/protein/sugar/polymer/biopolymer sequencing apparatus; or a filtration-related application such as water desalination, water purification, reverse electrodialysis, energy generation and gas separation.
  • the use of the atomically or molecularly thin amorphous carbon membrane as a TEM support grid significantly reduces background signal, without adding extra diffraction patterns, in order to improve the resolution of the TEM process.
  • the atomically or molecularly thin amorphous carbon membrane is chemically inert.
  • Ion or proton selective membranes are required in the applications of water filtration, desalination, and fuel cells. Since ion conductivity scales inversely with the membrane thickness, the use of the atomically or molecularly thin amorphous carbon membrane as an ion or proton selective membrane provides lower internal resistance and thereby enhances the performance of such applications.
  • the listing or discussion of an apparently prior published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

Abstract

There is provided a method of fabricating an atomically or molecularly thin amorphous carbon membrane (18). The method includes the steps of: providing amphiphilic or hydrophobic carbon-containing monomers (10) on a liquid surface; packing the amphiphilic or hydrophobic carbon-containing monomers (10); and causing polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers (10) to form the amorphous carbon membrane (18).

Description

MEMBRANE AND METHOD OF MANUFACTURE THEREOF
This invention relates to an amorphous carbon membrane and a method of fabricating an amorphous carbon membrane.
It is known to use a membrane as a selective barrier for a wide range of applications.
According to a first aspect of the invention, there is provided a method of fabricating an atomically or molecularly thin amorphous carbon membrane, the method including the steps of: providing amphiphilic or hydrophobic carbon-containing monomers on a liquid surface; packing the amphiphilic or hydrophobic carbon-containing monomers; and causing polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers to form the amorphous carbon membrane.
The method of the invention facilitates the assembly of an atomically or molecularly thin amorphous carbon membrane using a bottom-up approach that is not only compatible with the requirement to produce an atomic or molecular thickness but also readily adapted to tune the properties of the resultant amorphous carbon membrane with excellent reproducibility. The versatility of the method of the invention enables the creation of an atomically or molecularly thin amorphous carbon membrane with tunable properties for use in a wide range of applications and devices.
The method enables the manufacture of an atomically or molecularly thin amorphous carbon membrane with a controllable thickness, e.g. through selection of a suitable type of monomer and/or packing conditions and/or polymerisation conditions. Hence, a consistent thickness throughout the amorphous carbon membrane can be provided, thus facilitating large-area fabrication of an atomically or molecularly thin amorphous carbon membrane.
In embodiments of the invention, the amorphous carbon membrane may have a nanometre-scale thickness or a sub-nanometre-scale thickness. The thickness of the amorphous carbon membrane may be from 0.3 nm to 3.0 nm or may correspond to any 0.01 nm interval in the range of 0.3 nm and 3.0 nm. In further embodiments of the invention, the method may include the step of forming pores during the formation of the amorphous carbon membrane, wherein each pore is a nanopore or a sub-nanopore. In such embodiments, a width of each pore is from 0.01 nm to 100 nm. Preferably the pores of the resultant amorphous carbon membrane consist of pores with widths from 0.01 nm to 100 nm, that is to say the resultant amorphous carbon membrane does not include one or more pores with a width outside the range of 0.01 nm to 100 nm. One or more pores may have a width corresponding to any 0.01 nm interval in the range of 0.01 nm and 100 nm.
The method of the invention enables the creation of natural nanopores and/or sub nanopores during the synthesis of the amorphous carbon membrane and thus allows the fabrication of an atomically or molecularly thin amorphous carbon membrane with nanoporosity and/or sub-nanoporosity in its pristine state, without requiring additional steps to artificially introduce nanopores and/or sub- nanopores into the amorphous carbon membrane. This in turn is conducive to large-area fabrication of atomically or molecularly thin amorphous carbon membranes with nano-porosity and/or sub-nanoporosity. Furthermore, the method of the invention enables tuning of the size of each pore, e.g. through selection of a suitable type of monomer and/or packing conditions and/or polymerisation conditions, in order to obtain a desired level of porosity resolution.
The method of the invention therefore obviates the need for creating artificial nanopores and/or sub- nanopores in the amorphous carbon membrane post-formation using transmission electron microscope (TEM) sputtering or lithographic techniques, both of which due to slow processing speeds and high cost are not suitable for large-area fabrication of atomically or molecularly thin amorphous carbon membranes with nanoporosity and/or sub-nanoporosity.
In still further embodiments of the invention, the method may include the step of aligning or orienting the amphiphilic or hydrophobic carbon-containing monomers on the liquid surface prior to their packing.
Optionally the step of packing the amphiphilic or hydrophobic carbon-containing monomers may include using at least one barrier to compress the amphiphilic or hydrophobic carbon-containing monomers. The or each barrier may be manually operated or automatically operated in order to provide precise control over the packing of the amphiphilic or hydrophobic carbon-containing monomers. The method of the invention may include the step of providing a precursor source that contains the amphiphilic or hydrophobic carbon-containing monomers. This provides a reliable means of providing the amphiphilic or hydrophobic carbon-containing monomers on the liquid surface. For example, the precursor source may be a solution that contains the amphiphilic or hydrophobic carbon-containing monomers.
The choice of monomers depends on the desired properties of the resultant amorphous carbon membrane. The amphiphilic or hydrophobic carbon-containing monomers may be hexa(2,2'-dipyridylamino)hexabenzocoronene (HPAHBC) monomers, hexa(2,2':6',2"- terpyridin-4'-yl)phenylbenzene (TRY) monomers or hexa(4-methylphenyl)benzene (HMPB) monomers. The amphiphilic or hydrophobic carbon-containing monomers may be polyaromatic monomers or polycyclic aromatic hydrocarbons. Preferably each polyaromatic monomer includes a polyaromatic core moiety and a functionalised rim moiety connected to and surrounding the polyaromatic core moiety.
Polymerisation between at least some of the packed amphiphilic or hydrophobic carbon- containing monomers may take place via a wide range of reaction mechanisms depending on the chemical structures of the amphiphilic or hydrophobic carbon-containing monomers. For example, the polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers may include crosslinking of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers. Preferably the crosslinking of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers includes thermal annealing of the packed amphiphilic or hydrophobic carbon- containing monomers.
In embodiments of the invention, the amorphous carbon membrane may be freestanding.
In further embodiments of the invention, the method may include the step of transferring the packed amphiphilic or hydrophobic carbon-containing monomers from the liquid surface to a target substrate before the polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers to form the amorphous carbon membrane.
Transferring the packed amphiphilic or hydrophobic carbon-containing monomers to the target substrate facilitates the polymerisation of the packed amphiphilic or hydrophobic carbon-containing monomers and the post-processing of the amorphous carbon membrane for use in an application or a device, e.g. by transporting the packed amphiphilic or hydrophobic carbon-containing monomers to a new location to carry out their polymerisation and/or by using the target substrate as a support structure for the amorphous carbon membrane during the post-processing and/or in the application or device.
According to a second aspect of the invention, there is provided an atomically or molecularly thin amorphous carbon membrane comprising polymerised amphiphilic or hydrophobic carbon-containing monomers.
The features and advantages of the method of the first aspect of the invention and its embodiments apply mutatis mutandis to the features and advantages of the amorphous carbon membrane of the second aspect of the invention and its embodiments.
The amorphous carbon membrane may have a nanometre-scale thickness or a sub- nanometre-scale thickness. The thickness of the amorphous carbon membrane may be from 0.3 nm to 3.0 nm or may correspond to any 0.01 nm interval in the range of 0.3 nm and 3.0 nm.
The amorphous carbon membrane may include natural nanopores. A width of each nanopore may be from 0.01 nm to 100 nm. Preferably the nanopores of the resultant amorphous carbon membrane consist of nanopores with widths from 0.01 nm to 100 nm, that is to say the resultant amorphous carbon membrane does not include one or more nanopores with a width outside the range of 0.01 nm to 100 nm. One or more nanopores may have a width corresponding to any 0.01 nm interval in the range of 0.01 nm and 100 nm.
The amphiphilic or hydrophobic carbon-containing monomers may be HPAHBC monomers, TPY monomers or HMPB monomers.
The amphiphilic or hydrophobic carbon-containing monomers may be polyaromatic monomers or polycyclic aromatic hydrocarbons. Preferably each polyaromatic monomer includes a polyaromatic core moiety and a functionalised rim moiety connected to and surrounding the polyaromatic core moiety.
The polymerised amphiphilic or hydrophobic carbon-containing monomers may be cross- linked. Preferably the polymerised amphiphilic or hydrophobic carbon-containing monomers are cross-linked and thermally annealed. The amorphous carbon membrane may be freestanding.
According to a third aspect of the invention, there is provided an atomically or molecularly thin amorphous carbon membrane obtainable through any one of the method of the first aspect of the invention and its embodiments described hereinabove.
The features and advantages of the method of the first aspect of the invention and its embodiments apply mutatis mutandis to the features and advantages of the amorphous carbon membrane of the third aspect of the invention and its embodiments.
The amorphous carbon membrane of the invention may be used in a wide range of applications. For example, a device comprising an atomically or molecularly thin amorphous carbon membrane according to any one of the amorphous carbon membranes of the second and third aspects of the invention and their embodiments described hereinabove, wherein the device is any one of:
• a filter, e.g. a water filter;
• a permeable barrier;
• a sequencing apparatus, e.g. a sequencing apparatus for DNA or protein or sugar or polymer or biopolymer sequencing;
• a desalination apparatus, e.g. a water desalination apparatus;
• a purification apparatus, e.g. a water purification apparatus;
• an energy generation apparatus, e.g. a fuel cell such as a direct methanol fuel cell; · an energy storage apparatus;
• a gas separation apparatus;
• a support structure for a transmission electron microscopy (TEM) sample, e.g. a TEM support grid;
• an electrodialysis apparatus, such as a reverse electrodialysis apparatus.
Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, and the claims and/or the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and all features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.
A preferred embodiment of the invention will now be described, by way of a non-limiting example, with reference to the accompanying drawings in which:
Figure 1 shows a method of fabricating an amorphous carbon membrane according to an embodiment of the invention;
Figures 2a and 2b show exemplary monomers for use in the method of Figure 1;
Figure 3 shows a photograph of an amorphous carbon membrane sample prepared using the method of Figure 1;
Figure 4 shows optical images of amorphous carbon membranes prepared using the method of Figure 1;
Figure 5 shows Raman spectra of monolayer amorphous carbon membranes prepared using the method of Figure 1;
Figures 6 and 7 shows 2D Raman mapping of amorphous carbon membranes prepared using the method of Figure 1;
Figures 8 and 9 show atomic force microscopy (AFM) images of amorphous carbon membranes prepared using the method of Figure 1 ;
Figure 10 shows a high resolution TEM image of an amorphous carbon membrane prepared using the method of Figure 1;
Figure 11 shows a scanning electron microscopy (SEM) image of an amorphous carbon membrane prepared using the method of Figure 1;
Figure 12 shows a reverse electrodialysis setup incorporating an amorphous carbon membrane prepared using the method of Figure 1; and
Figures 13 and 14 illustrate the characteristics of the reverse electrodialysis setup.
The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic form in the interests of clarity and conciseness.
The following embodiment of the invention is described with reference to a method of fabricating an atomically or molecularly thin amorphous carbon membrane using polyaromatic monomers and the use of the amorphous carbon membrane in a reverse electrodialysis apparatus. It will be appreciated that the following embodiment of the invention is applicable mutatis mutandis to the fabrication of an atomically or molecularly thin amorphous carbon membrane using other types of amphiphilic or hydrophobic monomers and the use of the amorphous carbon membrane in other types of applications and devices.
A method of fabricating an atomically or molecularly thin amorphous carbon membrane is shown in Figure 1. The method is described with reference to HPAHBC monomers 10 but it will be appreciated that the HPAHC monomers 10 may be replaced by TPY monomers, HMPB monomers, other polyaromatic monomers (preferably with a polyaromatic core moiety and a functionalised rim moiety connected to and surrounding the polyaromatic core moiety), polycyclic aromatic hydrocarbons or other amphiphilic or hydrophobic monomers.
Initially a trough 12 is filled with water. Using a syringe, a solution 14 of a predetermined amount of chloroform solution containing HPAHBC monomers 10 is introduced drop-wise into a region of the water that is located between two barriers 16. The chloroform solution then evaporates, leaving the HPAHBC monomers 10 to cover the available area on the water surface. The pair of barriers 16 are then brought together to compress the monolayer to a specific surface pressure (e.g. 3 mN nr1, 10 mN nr1, 20 mN nr1 and 30 mN nr1) to increase the packing density of the HPAHBC monomers 10, which self-assemble on the water surface to form a dense monolayer of HPAHBC monomers 10. This results in a Langmuir film in the form of a monolayer of HPAHBC monomers 10 that are arranged and aligned on the air- water interface. The alignment of the HPAHBC monomers 10 and the formation of the monolayer of HPAHBC monomers 10 on the water surface are due to the amphiphilic nature of the HPAHBC monomers 10. In other embodiments, it is envisaged that the water in the trough 12 may be replaced by a different liquid and/or the trough 12 may be immersed in a different liquid or a gas so as to create a different gas-liquid or liquid-liquid interface.
The barriers 16 may be manually operated or automatically operated, e.g. using a computer-controlled actuator.
A flat solid copper substrate is brought into proximity with the monolayer of HPAHBC monomers 10 so as to permit horizontal deposition of the monolayer of HPAHBC monomers 10 onto a surface of the copper substrate. This results in a Langmuir-Schaefer film of HPAHBC monomers 10 adsorbed on the copper substrate. The Langmuir-Schaefer film of HPAHBC monomers 10 is then subjected to conditions that are suitable for crosslinking the HPAHBC monomers 10 in a polymerisation step to form an amorphous carbon membrane 18. For example, the Langmuir-Schaefer film of HPAHBC monomers 10 is thermally annealed in an oven at 550°C or higher under vacuum (e.g. 1 mbar, Argon atmosphere) for 15-20 minutes to form the crosslinked amorphous carbon membrane 18.
It will be appreciated that other types of solid substrates, such as a silicon substrate, may be used in place of the copper substrate.
In other embodiments of the invention, it is envisaged that the solid substrate may be oriented and dipped into the water to permit vertical deposition of a film of HPAHBC monomers. In such embodiments, the film of HPAHBC monomers on the solid substrate is referred to as a Langmuir-Blodgett film.
The atomically thin amorphous carbon membrane has a sub-nanometre-scale thickness. The molecularly thin amorphous carbon membrane has a nanometre-scale thickness or a sub-nanometre-scale thickness. Preferably the thickness of the amorphous carbon membrane may be from 0.3 nm to 3.0 nm or may correspond to any 0.01 nm interval in the range of 0.3 nm and 3.0 nm.
Preferably the amorphous carbon membrane comprises pores having a narrow size distribution in the range of 0.01 nm to 100 nm, where one or more pores may have a width corresponding to any 0.01 nm interval in the range of 0.01 nm and 100 nm.
The method of Figure 1 may be adapted to tune the thickness and pore size of the amorphous carbon membrane.
The thickness and pore size of the amorphous carbon membrane may be controlled by selecting a suitable type of amphiphilic or hydrophobic monomer. For example, the amphiphilic or hydrophobic carbon-containing monomers with different functional groups may be chosen in order to vary the thickness and nanopore size of the amorphous carbon membrane.
The thickness of the amorphous carbon membrane can be tuned by choosing different monomers. For instance, HPAHBC monomers have a strong tt-p stacking effect and have a tendency to stand vertically on the water surface, thus resulting in an amorphous carbon membrane thickness of 2 nm that is close to the size of a HPAHBC monomer. TPY monomers have a weak tt-p stacking effect due to the non-conjugated structure and have a tendency to stay flat on the water surface, with the maximum number of hydrogen bonds formed between pyridine and water, thus resulting in an amorphous carbon membrane thickness of 0.35 nm that is the thickness of a TRY molecule. HMPB monomers have a weak tt-p stacking effect but have a tendency to tilt on the water surface and are not as well aligned on the water surface due to their hydrophobic nature, thus resulting in an amorphous carbon membrane thickness of 0.8-0.9 nm.
The pore size of the amorphous carbon membrane can be tuned by choosing different monomers. For example, the amphiphilic nature of HPAHBC monomers results in excellent alignment of the HPAHBC monomers on the water surface, thus resulting in small pores following the packing and polymerisation steps. In comparison, the hydrophobic HMPB monomers do not align as well as the HPAHBC monomers on the water surface, thus resulting in comparatively larger pores following the packing and polymerisation steps. The compression speed and/or the degree of compression of the monolayer may be controlled to affect the packing of the monomers and thereby influence the subsequent polymerisation of the monomers, which in turn influences the atomic/molecular thickness of the amorphous carbon membrane. In addition the thermal annealing conditions influence the atomic/molecular thickness of the amorphous carbon membrane.
The method of Figure 1 therefore not only permits control over the magnitude and consistency of the thickness of the amorphous carbon membrane so as to fabricate an atomically or molecularly thin amorphous carbon membrane but also enables the creation of natural nanopores and/or sub-nanopores during the synthesis of the amorphous carbon membrane and thus allows the fabrication of an atomically or molecularly thin amorphous carbon membrane with nanoporosity and/or sub-nanoporosity in its pristine state. As a result, the method of Figure 1 therefore facilitates the large-area assembly of an atomically or molecularly thin amorphous carbon membrane (e.g. at least a few square centimetres or larger) using a reproducible bottom-up approach.
To illustrate the properties of the resultant atomically or molecularly thin amorphous carbon membrane obtainable using the method of Figure 1 , three kinds of atomically or molecularly thin amorphous carbon membranes have been synthesized using HPAHBC monomers, TPY monomers and HMPB monomers respectively. Figure 2a shows the chemical structures of the HPAHBC monomers, TPY monomers and HMPB monomers. Figure 2b illustrates a non-limiting exemplary synthesis route for the HPAHBC monomers, each of which consists of six flexible dipyridylamino groups as the rim and one hexabenzocoronene (HBC) rigid core. A mixture of dipyridylamine (e.g. 0.34 g, 2.0 mmol), hexabromohexabenzocoronene (e.g. 0.10 g, 0.1 mmol), K2CO3 (e.g. 0.14 g, 1.0 mmol) and CuSC (e.g. 0.01 g, 0.06 mmol) was placed in a 10 ml flask and heated at 190 °C under N2 for several days (e.g. 4 days). After the reaction, the resultant black solid was first dissolved in dichloromethane (DCM) and filtered. The filtration was concentrated in vacuo, and purified by chromatography with DCM as eluent (e.g. 0.04 g, yield 26%) so as to produce the HPAHBC monomers.
TYP monomers and HMPB monomers are known in the art.
The following figures exemplarily describe properties of the resultant amorphous carbon membranes.
Figure 3 is a photograph of an amorphous carbon membrane prepared from TPY monomers and transferred to a silicon wafer. Despite the atomic or molecular thinness of the amorphous carbon membrane as indicated by its near-invisibility in the photograph, the amorphous carbon membrane has a comparatively large area of about 3.5 by 2.0 cm2. Similarly, Figure 4 shows optical images of sections of amorphous carbon membranes prepared from HPAHBC monomers (left image) and TPY monomers (right image), showing the ability of the method of Figure 1 to produce large area amorphous carbon membranes with atomic or molecular thinness indicated by their near-invisibility in the optical images.
Figure 5 shows Raman spectra of monolayer amorphous carbon membranes prepared from HPAHBC monomers (left image), TPY monomers (middle image) and HMPB monomers (right image). It can be seen from the left image of Figure 5 that the amorphous carbon membrane consists of the HPAHBC monomers by virtue of their almost identical Raman signals. No signal was observed for the TPY monomers and HMPB monomers due to their less conjugated chemical structures.
Figure 6 shows a 2D Raman mapping over a scan area of 50 pm by 50 pm of an amorphous carbon membrane prepared from TPY monomers, including a histogram of intensity ratio between D and G peaks. A Gaussian fitting curve is applied to the histogram. The intensity ratio between the D and G peaks is around 2.14 over the whole scan area, with a standard deviation of 6.9%. This indicates that the resultant amorphous carbon membrane exhibits relatively uniform thickness over the scan area.
Figure 7 shows a 2D Raman mapping over a scan area of 50 pm by 50 pm of an amorphous carbon membrane prepared from HMPB monomers. A Gaussian fitting curve is applied to the histogram. The intensity ratio between the D and G peaks is around 1.70 over the whole scan area, with a standard deviation of 7.1 %. This indicates that the resultant amorphous carbon membrane exhibits relatively uniform thickness over the scan area.
As a result, it is shown that the method of Figure 1 can be used to produce a controlled uniform thickness of amorphous carbon membranes prepared from different monomers.
Figure 8 shows AFM images of amorphous carbon membranes prepared from HPAHBC monomers (left image), TPY monomers (middle image) and HMPB monomers (right image). The thickness of the HPAHBC monomer-based amorphous carbon membrane is about 2.0 nm. The thickness of the TPY monomer-based amorphous carbon membrane is about 0.36 nm. The thickness of the HMPB monomer-based amorphous carbon membrane is about 0.80 nm. This shows the ability of the method of Figure 1 to tune the atomic or molecular thinness of the amorphous carbon membrane through the selection of a suitable monomer.
Figure 9 shows AFM images, at different magnifications, of an amorphous carbon membrane prepared from HMPB monomers. It can be seen from Figure 9 that natural nanopores in the range of 10 nm to 100 nm are formed in the amorphous carbon membrane using the method of Figure 1.
Figure 10 shows a high resolution TEM image of an amorphous carbon membrane prepared from HPAHBC monomers. The histogram in Figure 10 shows that a substantial percentage of natural nanopores of about 3.6 nm in diameter or less are formed in the amorphous carbon membrane using the method of Figure 1.
Figure 11 shows an SEM image of an amorphous carbon membrane prepared from HPAHBC monomers and transferred to a solid substrate with 2 pm wide holes. The scale bar in the SEM image is 4 pm long. It can be seen from Figure 11 that the amorphous carbon membrane is mechanically strong enough to be freestanding over the 2 pm wide holes. The versatility of the method of Figure 1 enables the creation of a 2D amorphous carbon membrane with nanometre-scale and/or sub-nanometre-scale pore structures, the properties of which can be readily tuned to suit the requirements of a wide range of applications and devices. Particularly, the properties of the nanopores and/or subnanopores can be tuned to define proton, ion and/or small molecular selective nanopore and/or sub-nanopore structures.
Figure 12 shows a reverse electrodialysis apparatus incorporating an HPAHBC monomer- based amorphous carbon membrane 22 that is prepared using the method of Figure 1 and is cation selective with a selectivity of about 40%. The HPAHBC monomer-based amorphous carbon membrane 22 is arranged in a KCI solution gradient. A voltage is applied across the KCI solution and membrane arrangement using Ag/AgCI electrodes 24 connected to the arrangement via respective salt bridges 26.
Figure 13 illustrates, in graph form, the variation in short-circuit current and open-circuit potential as a function of salt concentration gradient. The short-circuit current and open- circuit potential are commonly measured quantities for assessing the performance of a reverse electrodialysis apparatus. It can be seen from Figure 13 that the HPAHBC monomer-based amorphous carbon membrane prepared using the method of Figure 1 can be used as an ion- selective membrane to directly generate electricity in the reverse electrodialysis apparatus.
Figure 14 illustrates, in graph form, the variation in current density and the corresponding output power density of the reverse electrodialysis apparatus as a function of the load resistance. It can be seen from Figure 14 that the use of the HPAHBC monomer-based amorphous carbon membrane in the reverse electrodialysis apparatus produces a high- short circuit current with a maximum output power density of 67 W/m2, which is about two orders of magnitude higher than the output power density produced by reverse electrodialysis apparatus using conventional polymer membranes.
The atomically or molecularly thin amorphous carbon membranes of the invention may be used in a range of other applications and devices, some non-limiting examples of which are described as follows.
The atomically or molecularly thin amorphous carbon membrane may be used to select and/or separate molecules from a retentate, where the molecules are able to permeate the nanopores of the amorphous carbon membrane based on the charge, size and shape of the molecules.
The separation of molecules may be performed in any one of: a direct methanol fuel cell; a DNA/protein/sugar/polymer/biopolymer sequencing apparatus; or a filtration-related application such as water desalination, water purification, reverse electrodialysis, energy generation and gas separation.
The use of the atomically or molecularly thin amorphous carbon membrane as a TEM support grid significantly reduces background signal, without adding extra diffraction patterns, in order to improve the resolution of the TEM process. In addition, the atomically or molecularly thin amorphous carbon membrane is chemically inert.
Ion or proton selective membranes are required in the applications of water filtration, desalination, and fuel cells. Since ion conductivity scales inversely with the membrane thickness, the use of the atomically or molecularly thin amorphous carbon membrane as an ion or proton selective membrane provides lower internal resistance and thereby enhances the performance of such applications. The listing or discussion of an apparently prior published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.
Preferences and options for a given aspect, feature or parameter of the invention should, unless the context indicates otherwise, be regarded as having been disclosed in combination with any and all preferences and options for all other aspects, features and parameters of the invention.

Claims

1. A method of fabricating an atomically or molecularly thin amorphous carbon membrane, the method including the steps of: providing amphiphilic or hydrophobic carbon-containing monomers on a liquid surface; packing the amphiphilic or hydrophobic carbon-containing monomers; and causing polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers to form the amorphous carbon membrane.
2. A method according to Claim 1 wherein the amorphous carbon membrane has a nanometre-scale thickness or a sub-nanometre-scale thickness.
3. A method according to Claim 1 or Claim 2 including the step of forming pores during the formation of the amorphous carbon membrane, wherein each pore is a nanopore or a sub-nanopore.
4. A method according to Claim 3 wherein a width of each pore is from 0.01 nm to 100 nm.
5. A method according to any one of the preceding claims including the step of aligning or orienting the amphiphilic or hydrophobic carbon-containing monomers on the liquid surface prior to their packing.
6. A method according to any one of the preceding claims wherein the step of packing the amphiphilic or hydrophobic carbon-containing monomers includes using at least one barrier to compress the amphiphilic or hydrophobic carbon-containing monomers.
7. A method according to any one of the preceding claims including the step of providing a precursor source that contains the amphiphilic or hydrophobic carbon- containing monomers.
8. A method according to any one of the preceding claims wherein the amphiphilic or hydrophobic carbon-containing monomers are HPAHBC monomers, TPY monomers or HMPB monomers.
9. A method according to any one of the preceding claims wherein the amphiphilic or hydrophobic carbon-containing monomers are polyaromatic monomers or polycyclic aromatic hydrocarbons.
10. A method according to any one of the preceding claims wherein the polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers includes crosslinking of at least some of the packed amphiphilic or hydrophobic carbon- containing monomers.
11. A method according to Claim 10 wherein the crosslinking of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers includes thermal annealing of the packed amphiphilic or hydrophobic carbon-containing monomers.
12. A method according to any one of the preceding claims wherein the amorphous carbon membrane is freestanding.
13. A method according to any one of the preceding claims including the step of transferring the packed amphiphilic or hydrophobic carbon-containing monomers from the liquid surface to a target substrate before the polymerisation of at least some of the packed amphiphilic or hydrophobic carbon-containing monomers to form the amorphous carbon membrane.
14. An atomically or molecularly thin amorphous carbon membrane comprising polymerised amphiphilic or hydrophobic carbon-containing monomers.
15. An atomically or molecularly thin amorphous carbon membrane according to Claim 14 wherein the amorphous carbon membrane has a nanometre-scale thickness or a sub- nanometre-scale thickness.
16. An atomically or molecularly thin amorphous carbon membrane according to Claim 14 or Claim 15 wherein the amorphous carbon membrane includes natural pores and wherein each pore is a nanopore or a sub-nanopore.
17. An atomically or molecularly thin amorphous carbon membrane according to Claim 16 wherein a width of each pore is from 0.01 nm to 100 nm.
18 An atomically or molecularly thin amorphous carbon membrane according to any one of Claims 14 to 17 wherein the amphiphilic or hydrophobic carbon-containing monomers are HPAHBC monomers, TRY monomers or HMPB monomers.
19. An atomically or molecularly thin amorphous carbon membrane according to any one of Claims 14 to 18 wherein the amphiphilic or hydrophobic carbon-containing monomers are polyaromatic monomers or polycyclic aromatic hydrocarbons.
20. An atomically or molecularly thin amorphous carbon membrane according to any one of Claims 14 to 19 wherein the polymerised amphiphilic or hydrophobic carbon- containing monomers are cross-linked.
21. An atomically or molecularly thin amorphous carbon membrane according to Claim 20 wherein the polymerised amphiphilic or hydrophobic carbon-containing monomers are cross-linked and thermally annealed.
22. An atomically or molecularly thin amorphous carbon membrane according to any one of Claims 14 to 21 wherein the amorphous carbon membrane is freestanding.
23. An atomically or molecularly thin amorphous carbon membrane obtainable through the method of any one of Claims 1 to 13.
24. A device comprising an atomically or molecularly thin amorphous carbon membrane according to any one of Claims 14 to 23, wherein the device is any one of:
• a filter;
• a permeable barrier;
• a sequencing apparatus;
• a desalination apparatus;
• a purification apparatus;
• an energy storage apparatus;
• an energy generation apparatus;
• a gas separation apparatus;
• a support structure for a transmission electron microscope sample;
• an electrodialysis apparatus.
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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017072272A1 (en) * 2015-10-28 2017-05-04 Cnm Technologies Gmbh Method for manufacturing of a carbon nanomembrane

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017072272A1 (en) * 2015-10-28 2017-05-04 Cnm Technologies Gmbh Method for manufacturing of a carbon nanomembrane

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DANIEL J. MURRAY ET AL: "Large Area Synthesis of a Nanoporous Two-Dimensional Polymer at the Air/Water Interface", JOURNAL OF THE AMERICAM SOCIETY, vol. 137, no. 10, 26 February 2015 (2015-02-26), US, pages 3450 - 3453, XP055722548, ISSN: 0002-7863, DOI: 10.1021/ja512018j *
POLINA ANGELOVA ET AL: "A Universal Scheme to Convert Aromatic Molecular Monolayers into Functional Carbon Nanomembranes", ACS NANO, vol. 7, no. 8, 27 August 2013 (2013-08-27), pages 6489 - 6497, XP055236230, ISSN: 1936-0851, DOI: 10.1021/nn402652f *
THOMAS BAUER ET AL: "Synthesis of Free-Standing, Monolayered Organometallic Sheets at the Air/Water Interface", ANGEWANDTE CHEMIE INT ED, vol. 50, no. 34, 1 July 2011 (2011-07-01), DE, pages 7879 - 7884, XP055536486, ISSN: 1433-7851, DOI: 10.1002/anie.201100669 *

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