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WO2015168411A1 - Films et procédés de formation de films à base de structures en un nanomatériau de carbone - Google Patents

Films et procédés de formation de films à base de structures en un nanomatériau de carbone Download PDF

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Publication number
WO2015168411A1
WO2015168411A1 PCT/US2015/028524 US2015028524W WO2015168411A1 WO 2015168411 A1 WO2015168411 A1 WO 2015168411A1 US 2015028524 W US2015028524 W US 2015028524W WO 2015168411 A1 WO2015168411 A1 WO 2015168411A1
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Prior art keywords
substrate
artificial
carbon
group
initiator
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Balaji Sitharaman
Sunny C. PATEL
Gaurav LALWANI
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Research Foundation of the State University of New York
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Research Foundation of the State University of New York
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/28—Materials for coating prostheses
    • A61L27/30—Inorganic materials
    • A61L27/303—Carbon
    • 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
    • C01B32/152—Fullerenes
    • C01B32/156—After-treatment
    • 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
    • C01B32/158—Carbon nanotubes
    • C01B32/159—Carbon nanotubes single-walled
    • 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
    • C01B32/18—Nanoonions; Nanoscrolls; Nanohorns; Nanocones; Nanowalls
    • 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
    • C01B32/198—Graphene oxide
    • 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
    • C01B32/20—Graphite
    • C01B32/21—After-treatment
    • C01B32/23—Oxidation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2400/00—Materials characterised by their function or physical properties
    • A61L2400/12—Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures

Definitions

  • CVD Chemical Vapor Deposition
  • vacuum filtration requires temperatures up to 1000°C and vacuum filtration requires flat substrates.
  • CVD method requires very specific substrates for nanomaterial film growth or deposition. For example, direct growth of carbon nanotube forests or graphene coatings by CVD requires substrates that can withstand both high temperatures and pressures.
  • the present disclosure is directed to methods of forming a carbon film and substrates, upon which carbon films can be formed.
  • the method of the current disclosure includes forming a carbon film by mixing a carbon nanomaterial with an initiator to form a mixture of nanomaterial and initiator, placing the mixture on a surface of a substrate and maintaining the mixture and substrate at a temperature above room temperature for a period of time to form the film.
  • the substrate includes a carbon film formed on a surface of the substrate and the substrate being thermally stable up to about 120°C.
  • FIG. 1 A is an illustration of an in situ carbon film forming process
  • FIG. IB is photograph of film standing vertically (top photograph) and tilted to illustrate substantial transparency (bottom photograph).
  • FIG.2A is a graphical illustration of Raman spectroscopy for Multi Walled Carbon Nanotube (MWCNT) crosslinked films with three different mass ratios of MWCNT:BP;
  • FIG. 2B is a graphical representation of the variation in Raman Band Ratio
  • FIGs. 3A-3F are SEM images of graphene nano-onions, nanoribbons and nanoplatelets
  • FIG. 4 are Atomic Force Microscopy (AFM) images of ultrasonic spray coated carbon materials
  • FIGs. 5A-5E are Scanning Electron Microscope (SEM) images of ultrasonic spray coated carbon materials
  • FIGs. 6A-6F are representative SEM and TEM micrographs for 1 :4 MWCNT films.
  • FIG. 6 A is an overview micrograph with a cross-sectional inset (scale bar ⁇ )
  • FIG. 6B indicates formed crosslinks between nanotubes
  • FIG. 6C and FIG. 6D are magnified views of what is shown in FIG. 6B
  • FIG. 6E is a TEM image of a single crosslink junction with FIG. 6F indicating the directions of intersecting MWCNT lattice shown by the arrows;
  • FIG. 7 is a representative AFM image of 1 :4 MWCNT films, on silicon wafer, indicating topography created by the mesh network of carbon nanotubes;
  • FIG. 8 is representative load-unloading curve from nanoindentiation of spray coated non-crosslinked pristine MWCNT and crosslinked MWCNT (1 :4);
  • FIGs. 9A-9E are graphical representations of cell proliferation and toxicity for ADSCs (FIG. 9A and FIG. 9C) and MC3T3-E1 cells (FIG. 9B and FIG. 9D) on ADSCs (FIG. 9A and FIG. 9C) and MC3T3-E1 cells (FIG. 9B and FIG. 9D) on
  • FIGs. 9E and 9F are graphical representations of LDH release over time
  • FIGs. 10A-10D are representative images of proliferation marker Ki-67 and actin immunofluorescence for ADSCs grown on glass coverslips (FIG.1 OA and FIG. 10B) and MWCNT crosslinked substrates (FIG. IOC and FIG. 10D);
  • FIGs. 1 1A— 1 IF are representative SEM images of adipose derived stem cells grown on MWCNT substrates, circles in FIG. 11 A and FIG. 11C, magnified in FIG. 1 IB and FIG. 1 ID respectively, with arrows showing cell adhesion by wrapping around nanotubes, FIG. 1 IB, or cell protrusions going underneath nanotube structures, FIG. 1 ID, FIGs. 1 IE and 1 IF illustrate the uniaxial cytoplasmic elongation on the MWCNT films;
  • FIGs. 12A-12C are representative confocal fluorescence microscopy of ADSCs stained with and Hoechst 33342 (two-photon ⁇ - grown on glass coverslips (FIG. 12A) and MWCNT crosslinked substrates (FIG. 12B and FIG. 12C) for 5 days at 37°C;
  • FIG. 13 is a Raman spectra of SWCNT crosslinked with varying crosslinking agents.
  • FIG. 14 is AFM images of SWCNT crosslinked with varying crosslinking agents. DETAILED DESCRIPTION OF THE DISCLOSURE
  • crosslinked refers to a process, in which at least two molecules, or two portions of a molecule, are joined together by a chemical interaction. Such interactions may occur in many different ways including formation of a covalent bond, formation of hydrogen bonds, hydrophobic, hydrophilic, ionic or electrostatic interaction. Furthermore, molecular interaction may also be characterized by an at least temporary physical connection between at least one molecule of carbon nanomaterial with itself or between two or more molecules. Therefore, it is contemplated that a crosslinked nanomaterial may crosslink with itself.
  • Crosslinking can be mediated by various reactive groups, and may occur by numerous mechanisms. If a covalent bond is formed between two reactive groups, it may be formed by a variety of chemical reaction mechanisms, including additions, eliminations or substitutions. Examples are nucleophilic or electrophilic addition, El- or E2-type eliminations, nucleophilic and aromatic substitutions. Crosslinking may be a spontaneous process or may require energy or a catalyst. Examples of such energy are thermal energy, radiation, mechanic, electric or electromagnetic energy. Examples of catalysts are acids, bases, and palladium-coated activated charcoal. Also, crosslinking may or may not involve extrinsic crosslinkers, and any extrinsic crosslinker may comprise single molecules, crosslinking molecules may also themselves be oligomeric or even polymeric.
  • thermally stable refers to a substrate maintaining its shape and chemical structure after being heated to a given temperature for a period of time of a few hours to several days or weeks.
  • carbon nanotube refers to an elongated hollow structure having a cross section (e.g. angular fibers having edges) or a diameter (e.g. rounded) less than about 1 micron.
  • multiwalled carbon nanotube refers to carbon nanotubes which are substantially cylindrical, graphitic nanotubes of substantially constant diameter and comprise cylindrical graphitic sheets or layers whose c-axes are substantially perpendicular to their cylindrical axis.
  • graphene refers to a two dimensional single sheet of carbon or multiple sheets of carbon.
  • fullerene refers to a carbon compound in the form of a hollow sphere, ellipsoid, or tube.
  • graphene oxide nanoribbon refers to, for example, single- or multiple layers of graphene (typically less than 10 carbon layers thick) that have an aspect ratio of greater than about 5, based on their length and their width.
  • graphene oxide nanoplatelets refers to a planar-like nano-sized graphene oxide that is substantially solid.
  • grapheme oxide nano-onion shall mean hollow, porous, multi-wall carbon nanospheres or polyhedral structures with a narrow size distribution and an average particle size of approximately 80 nm and an average aspect ratio close to 7:5.
  • Such structures are also referred to as carbon Q-dots or Q-graphene and can be any suitable sp 2 hybridized carbon nanostructure.
  • the term “substantially”, or “substantial”, is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result.
  • a surface that is “substantially” flat would either completely flat, or so nearly flat that the effect would be the same as if it were completely flat.
  • the disclosure includes a method of forming a carbon film.
  • the method for forming the carbon film includes several steps, the first being mixing a carbon nanomaterial with an initiator to form a mixture of nanomaterial and initiator.
  • the carbon nanomaterial can be any suitable carbon nanomaterial, including but not limited to multi-walled carbon nanotubes (MWCNT), nanotubes, graphenes, fullerenes, graphene oxide nanoplatelets, graphene oxide nanoribbon, graphene oxide nano-ions and combinations thereof.
  • MWCNT multi-walled carbon nanotubes
  • the initiator can be any initiator that is suitable for forming crosslinked-carbon nanomaterial from the carbon nanomaterial, such as peroxides, or any radical initiator containing a peroxide functional group (ROOR'), hydroperoxides, peresters, and azo compounds, the like, and mixtures thereof.
  • suitable free radical initiators include benzoyl peroxide, methyl ethyl ketone peroxide, Di-tert-butyl peroxide, acetone peroxide, dicumyl peroxide, di-t-butyl peroxide, t- butylperoxybenzoate, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl
  • peroxyneodecanoate 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, t-amyl peroxypivalate, l,3-bis(t-butylperoxyisopropyl)benzene, tert-amylperoxy 2 -ethyl hexanoate, t- butylperoxy 2-ethyl hexanoate, t-butyl peroxy isobutyrate, t-butylperoxy isopropyl carbonate, t-butylperoxy 3,5,5-trimethylhexanoate, 2,5-dimethyl-2,5- di(benzolyperoxy)hexane, n-butyl 4,4-di(t-butylperoxy)valcratic, t-butylcumyl peroxide, di(2 -t-butylperoxy isopropyl)benzene, t-butyl hydro
  • Suitable azo compounds include 2,2'- azobisisopropionitrile, 2,2'-azobisisobutyronitrile (AIBN), dimethyl azoisobutyrate, 1,1'- azobis (cyclohexanecarbonitrile), 2,2'-azobis(2-methylpropane), the like, and mixtures thereof.
  • the first step can also include mixing a solvent to form a mixture of nanomaterial, initiator and solvent.
  • the solvent can be any suitable solvent, including organic solvents such as dimethylformamide (DMF), acetone, chloroform, ethyl acetate, tetrachloroethylene, carbon tetrachloride,
  • cyclohexene methyl benzoate, anisole, ethylbenzene, chlorobenzene, nitrobenzene, benzene, toluene, allyl acetate, styrene, cumene, iodobenzene, carbon disulfide, ethyl iodide, methylene chloride, ethyl chloride, bromobenzene, t-butylbenzene, maleic anhydride, ethyl bromide, allyl bromide, acetic anhydride, cyclohexane, acetic acid, pyridine, dioxane, diethyl ether, ethyl alcohol, m-cresol, aniline and triethylamine.
  • the ratio of carbon nanomaterial to initiator in the mixture can vary based on characteristics of the final carbon film. Some of the characteristics that can be modified by altering the ratio of carbon nanomaterial to initiator include surface roughness of the film, sheet resistivity, cytotoxicity and cell proliferation. The ratio of carbon
  • nanomaterial to initiator in the mixture can be in any suitable ratio, such as about 1 :0.5, about 1 : 1, about 1.5: 1, about 2: 1, about 2.5: 1, about 3: 1, about 3.5: 1 and about 4: 1.
  • FIG. 2A and FIG. 2B illustrate how the ratio of carbon nanomaterial to initiator affects Raman shift, Raman band ratio and Resistivity. Therefore, based on the prospective use of the mixture, the ratio can be modified based on the desired qualities of the carbon film.
  • Carbon nanotubes are known to be excellent conductors of electricity, and disruptions (due to functionalization of structural defects) to the sp 2 carbon network are known to decrease electrical conductivity of carbon nanotubes.
  • 1 : 1 (MWCNT:BP) samples showed greater sheet resistivity than pristine MWCNT coatings, a decrease in sheet resistivity was observed with increase in the defect sites in the MWCNT films to the point of recovery by 1 :4 (MWCNT:BP) (FIG. 2B).
  • one or more crosslinkers can be added to the mixture of carbon nanomaterial and initiator prior to the mixture being placed on a surface of a substrate.
  • These crosslinkers can include any suitable crosslinker, including but not limited to ethylene diacrylate, methylene bisacrylamide, divinyl benzene and mixtures thereof.
  • ethylene diacrylate ethylene diacrylate
  • methylene bisacrylamide divinyl benzene
  • mixtures thereof ethylene diacrylate, methylene bisacrylamide, divinyl benzene and mixtures thereof.
  • the combined mixture can be placed on a surface of a substrate and formed into a film as discussed below when referring to the mixture of carbon nanomaterial and initiator.
  • the mixture is placed on a surface of a substrate.
  • the mixture can be placed on the surface of the substrate in any suitable way, such as by a pressure driven or ultrasonic driven spraying device.
  • the substrate is thermally stable up to about 60°C, in other embodiments, the substrate is thermally stable up to about 120°C.
  • the substrate can be any suitable substrate for forming a carbon film and is at least one of a material with one or more substantially flat surfaces, a flexible material, a material with one or more curved surfaces or a material with one or more erratically shaped surfaces.
  • the suitable substrates include a whole or a part of a substrate selected from the group consisting of an implantable defibrillator, an artificial joint, a pacemaker, an implantable fixation element, a stent, a catheter, an artificial bone, an implantable drug delivery device, a cochlear implant, a suture, a valve, a tube, a guidewire, such as an ear tube, an implant such as a breast implant or chin implant, a balloon, a magnet, a power supply, a port, a sensor, a seed, a shunt and combinations thereof.
  • a substrate selected from the group consisting of an implantable defibrillator, an artificial joint, a pacemaker, an implantable fixation element, a stent, a catheter, an artificial bone, an implantable drug delivery device, a cochlear implant, a suture, a valve, a tube, a guidewire, such as an ear tube, an implant such as a breast implant or chin implant
  • an artificial hip ball included in the suitable artificial joints for forming a carbon film thereon are an artificial hip ball, an artificial hip socket, an artificial knee, an artificial finger joint, an artificial toe joint, an artificial shoulder, an artificial elbow, an artificial ankle.
  • implantable fixation devices for forming a carbon film thereon are one or more of screws, wires, rods, pins, plates, discs, meshes, dowels, cuffs, pegs, washers, bolts, nuts, anchors, clips, clamps and staples.
  • Suitable implantable drug delivery device for forming a carbon film thereon are an intra-uterine device, a catheter, an implantable insulin pump, an implantable drug pump and any suitable transdermal drug delivery system.
  • the mixture of the carbon nanomaterial and initiator is placed on a surface of a substrate, the mixture of nanomaterial and initiator is maintained at a temperature above room temperature for a period of time. After the period of time, the film is formed.
  • the mixture of nanomaterial and initiator can be maintained at the temperature above room temperature for any suitable amount of time, for instance up to about 24 hours.
  • any time from about 1 minute to about 24 hours is any time from about 1 minute to about 24 hours, including about 1 minute, about 30 minutes, about 1 hour, about 1.5 hours, about 2 hours, about 2.5 hours, about 3 hours, about 3.5 hours, about 4 hours, about 4.5 hours, about 5 hours, about 5.5 hours, about 6 hours, about 6.5 hours, about 7 hours, about 7.5 hours, about 8 hours, about 8.5 hours, about 9 hours, about 9.5 hours, about 10 hours, about 10.5 hours, about 11 hours, about 11.5 hours, about 12 hours, about 12.5 hours, about 13 hours, about 13.5 hours, about 14 hours, about 14.5 hours, about 15 hours, about 15.5 hours, about 16 hours, about 16.5 hours, about 17 hours, about 17.5 hours, about 18 hours, about 18.5 hours, about 19 hours, about 19.5 hours, about 20 hours, about 20.5 hours, about 21 hours, about 21.5 hours, about 22 hours, about 22.5 hours, about 23 hours, about 23.5 hours and about 24 hours.
  • the mixture of carbon nanomaterial and initiator can be maintained at any suitable temperature above room temperature that effects at least some crosslinking of the nanomaterial, including about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C or about 100°C.
  • the method of forming the carbon film includes an additional, optional step of increasing the temperature above room temperature to an increased temperature above room temperature for a period of time after the maintaining step.
  • This optional step can be used to remove any remaining initiator present in the carbon film.
  • the increased temperature above room temperature can be any temperature useful in removing a suitable initiator, including about 100°C, about 105°C, about 110°C, about 115°C, about 120°C, about 125°C, about 130°C, about 135°C, aboutl40°C, about 145°C, about 150°C, about 155°C, about 160°C, about 165°C, about 170°C, about 175°C, about 180°C, about 185°C, about 190°C, about 195°C or about 200°C.
  • the method of forming the carbon film includes another additional, optional step of contacting the carbon film with at least one reducing agent, such as hydrazine hydrate and ascorbic acid after the maintaining step.
  • This additional step may be useful in correcting or reducing oxidation defects that arise by reestablishing the sp 2 hybridization of the carbon film.
  • the present disclosure is also directed to a substrate that can have a carbon film formed on a surface of the substrate.
  • the substrate can be thermally stable up to about 120°C. In another embodiment, the substrate can be thermally stable up to about 60°C.
  • the carbon film formed on the substrate can comprise any suitable carbon nanomaterial, including but not limited to multi-walled carbon nanotubes (MWCNT), nanotubes, graphenes, fullerenes, graphene oxide nanoplatelets, graphene oxide nanoribbon, graphene oxide nano-ions and combinations thereof.
  • MWCNT multi-walled carbon nanotubes
  • nanotubes graphenes, fullerenes, graphene oxide nanoplatelets, graphene oxide nanoribbon, graphene oxide nano-ions and combinations thereof.
  • the substrate can be any suitable substrate for forming a carbon film and is at least one of a material with one or more substantially flat surfaces, a flexible material, a material with one or more curved surfaces or a material with one or more erratically shaped surfaces.
  • the suitable substrates include a whole or a part of a substrate selected from the group consisting of all implantable or external, medical or therapeutic devices, such as an implantable defibrillator, an artificial joint, a pacemaker, an implantable fixation element, a stent, an ear tube, an artificial bone, an implantable drug delivery device, a cochlear implant and combinations thereof.
  • implantable or external, medical or therapeutic devices such as an implantable defibrillator, an artificial joint, a pacemaker, an implantable fixation element, a stent, an ear tube, an artificial bone, an implantable drug delivery device, a cochlear implant and combinations thereof.
  • implantable fixation devices for forming a carbon film thereon are an artificial hip ball, an artificial hip socket, an artificial knee, an artificial finger joint, an artificial toe joint, an artificial shoulder, an artificial elbow, an artificial ankle.
  • suitable implantable fixation devices for forming a carbon film thereon are screws, wires, rods, pins, plates and discs
  • Suitable implantable drug delivery device for forming a carbon film thereon are an intra-uterine device, a catheter, an implantable insulin pump, an implantable drug pump and any suitable transdermal drug delivery system.
  • the implantable drug delivery device can be coated fully with the carbon film, or a portion of the implantable drug delivery device can be coated with the carbon film.
  • the drug to be delivered can be adsorbed or absorbed to the carbon film, the drug can be encapsulated in or on the carbon film, including encapsulation within polymeric spheres, and the drug can be included in or on the carbon film in fluorinated microbubbles.
  • Delivery of the drug from the carbon film can be facilitated in any suitable way, such as by diffusion, thermal agitation by variety of sources (e.g., optical, ultrasound, microwave and radiofrequency sources) and by photoacoustic disruption of the carriers (e.g.
  • sources e.g., optical, ultrasound, microwave and radiofrequency sources
  • photoacoustic disruption of the carriers e.g.
  • fluorinated microbubbles Any suitable drug could be delivered by this delivery device, including hydrophobic drugs and topical drugs.
  • FIGs. 3A-3F are low- magnification SEM images of crosslinked graphene oxide nano onions, graphene oxide nanoplatelets and graphene oxide nanoribbons.
  • FIGs. 3B, 3D and 3F are high magnification SEM images of crosslinked graphene oxide nano onions, graphene oxide nanoplatelets and graphene oxide nanoribbons.
  • the carbon films of the disclosure are versatile and can be adapted for different sp 2 hybridized allotropes of carbon including, but not limited to, various types of graphene (e.g., graphene nano-onions, nanoribbons and nanoplatelets, as shown in FIG. 4.
  • FIG. 4 is AFM images of ultrasonic spray coated graphene nanoplatelets (GONP), graphene oxide nanoribbons (GONR), single walled carbon nanotubes (SWCNT ) and MWCNT.
  • GONP ultrasonic spray coated graphene nanoplatelets
  • GONR graphene oxide nanoribbons
  • SWCNT single walled carbon nanotubes
  • MWCNT multi walled carbon nanotubes
  • the resulting mixture was sent through a glass syringe and injected at a constant rate through an ultrasonic spray nozzle.
  • An xyz gantry was used to raster the spray coating in x-y directions as well as maintain constant height from the coating substrate.
  • FIGs. 5A-5E includes scanning electron microscope (SEM) images of ultrasonic spray coated: SWCNT (FIG. 5 A); MWCNT of low diameter (FIG. 5B); MWCNT of high diameter (FIG. 5C); graphene nanoplatelets (FIG. 5D); and graphene oxide nanoribbons (FIG. 5E).
  • SEM scanning electron microscope
  • Spray coating allows coating of irregular shapes, and ability to create a continuous network (FIG. 2A) with a relatively high surface roughness ( ⁇ 730nm).
  • the droplet size inhomogeneity (as depicted in FIG. 1 A), and nanomaterial aggregation may be responsible for this roughness.
  • the use of the xyz gantry enable more control over the following three parameters: (1) the number of layers sprayed is controlled by the number of passes the xyz gantry, which holds the spray head, makes over the substrate; (2) the volume of nanomaterial suspension sprayed is controlled at a substantially constant rate by a syringe pump; and (3) there is a low operating pressure compared to air pressure driven spray techniques, resulting in less wasted material (for example about 2 p.s.i. for ultrasonic spray coating vs 30 p.s.i. for airbrush coating).
  • Ultrasonic spray coating can create functionalized-MWCNT films of 3 nm average surface roughness.
  • the chemical crosslinking of MWCNTs substantially enhances the mechanical properties of the films and thus, their structural stability compared to pristine non-crosslinked MWCNT films. This enhancement should prevent the films from disintegration under compressive flexural or shear forces under physiological conditions.
  • the mean surface roughness measurements for ultrasonic spray coated for GONP was 159.07 nm, for GONR was 169.5 nm, for SWCNT was 167.05 nm and for MWCNT was 120.51 nm.
  • Radical initiated thermal crosslinking of carbon nanomaterials combined with air- pressure driven spray coating technique allows in situ assembly of MWCNTs into chemically-crosslinked and mechanically robust MWCNT films.
  • This protocol can be adapted for other carbon nanostructures such as graphene (e.g., graphene nano onions, graphene nanoribbons and graphene nanoplatelets).
  • the crosslinked MWCNT films were found to be cytocompatible for human ADSCs. The results introduce a method to fabricate robust carbon nanotubes nanofiber mats for use in various medical applications.
  • Multi-walled carbon nanotubes were purchased from Sigma Aldrich with the outer wall diameters of about 110-170 nm and lengths of about 5-9 ⁇ .
  • Graphene oxide nanoplatelets (GONP) were synthesized and characterized.
  • Graphene oxide nanoribbons (GONR) were synthesized by longitudinal unzipping of multiwalled carbon nanotubes (Sigma Aldrich).
  • Graphene oxide nano-onions (GONO), also known as Q-graphene, were purchased from Graphene Supermarket (Calverton, NY).
  • Nanoparticle suspensions at 1 mg/mL in anhydrous ethyl acetate were dispersed by sonication for 15 minutes.
  • MWCNT to benzoyl peroxide (BP) mass ratios of 1 : 1, 1 :2, and 1 :4 were used for initial characterization. All cell studies, discussed below, were performed on the 1 :4 ratio samples.
  • Suspensions were sprayed with an air pressure driven spray device (Iwata HP- CS) onto 12mm diameter round glass coverslips (Electron Microscopy Sciences). A graphical representation of this is shown in FIG. 1A. As shown in this graphical representation, the thickness can be modulated from thin to thicker through the application process.
  • the MWCNTs completely coated the coverslips (FIG. IB, top) and were semi-transparent (FIG. IB, bottom).
  • coverslips were heated on a hotplate to about 60 C. This temperature is a cause of in situ crosslinking and prevents the liquid suspension from accumulating on the surface of the coverslips.
  • samples were further thermally crosslinked in an oven at 60 C for 12 hours.
  • excess BP was removed by heating the coated coverslips at 150 C for an additional 30 minutes.
  • This spraying method leads to the generation of substantially heterogeneously- sized droplets of MWCNT and benzoyl peroxide which deposit onto the heated coverslip.
  • the solvent ethyl acetate
  • Raman spectroscopy (Enwave Optronics) was performed in three regions of each sample under a 40x objective using a 532nm laser source. Point spectra scanning from 100 to 3,100 cm "1 at room temperature were acquired.
  • Scanning electron microscopy was performed using a JEOL 7600F analytical high resolution SEM. Samples were sputter coated with a 3ng layer of Au to prevent surface charge accumulation. Transmission electron microscopy (TEM) samples were prepared by fragmenting crosslinked films by scratching the surface with sharp tweezers and placing them on a conductive carbon TEM porous grid (PELCO, Ted Pella). TEM was performed using a JEOL JEM2100F high resolution analytical TEM. Both electron microscopy techniques were performed at Brookhaven National
  • Sheet resistivity was assessed by a four probe resistance measurement technique (Signatone S302-4, SP-4 probe) at Center for Functional Nanomaterials (CFN), Brookhaven National Laboratory, New York. Four spring-loaded probes, spaced equally by 1.25mm distances, were lowered onto glass coverslips coated with MWCNT (1 :4) to measure sheet resistance and resistivity.
  • Raman spectroscopy (Enwave Optronics, Irvine, CA) was performed in three regions of each sample (after thermal treatment to remove residual BP) under a 40x objective using a 532nm laser source. Point spectra scanning from 100 to 3,100 cm-1 at room temperature were acquired.
  • ADSCs Primary human adipose derived stem cells
  • FBS heat inactivated FBS
  • ADSC Growth Media BulletkitTM Lonza
  • Cells were grown in tissue culture treated polystyrene at 95% humidity, 5% C0 2 , at 37°C with media changes every three days.
  • Nanoparticle coated coverslips and plain coverslips (control) were washed with a sterile phosphate buffered saline solution (Gibco, New York) and sterilized under ultraviolet radiation for two hours.
  • Triton-X-100 permeabilizing buffer (10.3 g sucrose, 0.4 g HEPES buffer, 0.29 g NaCl, 0.06 g MgCl 2 , and 0.5 mL Triton-X-100 in 100 ml DI water) for 25 minutes.
  • Samples were washed using immunofluorescence buffer (IFB, 0.1% BSA and 0.1% Triton-X-100 in PBS) and incubated with commercially available monoclonal anti-proliferating i-67 antibody raised in mouse (2 ⁇ /mL in IFB, Cat. No. P8825, Sigma Aldrich, New York, USA) for 1 hour. Samples were washed with IFB (3X) and incubated with anti-mouse rhodamine conjugated secondary antibody (2 yLlmL in IFB, Cat. No. SAB3701218, Sigma Aldrich, New York, USA) for 1 hour.
  • Samples were washed with IFB (3X) and stained with FITC conjugated phalloidin (2 ⁇ LIvaL in PBS) for 1 hour to visualize cytoskeleton (actin filaments). Samples were then imaged using a confocal laser scanning microscope (Zeiss LSM 510 Two-Photon LSCM).
  • Specimens for scanning electron microscopy were prepared as follows. MWCNT 1:4 samples with ADSCs were dehydrated by serial ethanol wetting steps from 50% to anhydrous ethanol. The samples were then air dried for one day and vacuum dried overnight at room temperature. A 3nm layer of gold sputter was applied prior to SEM. SEM was performed on a high resolution analytical JOEL 7600F SEM at the Center for Functional Nanomaterials (Brookhaven National Laboratories).
  • FIG. 2A Normalized Raman spectra of crosslinked MWCNT films are presented in FIG. 2A. Each mass ratio showed the characteristic Raman peaks of MWCNT with D, G, and G' bands at ⁇ 1345 cm “1 , 1560 cm “1 , and 2670 cm “1 , respectively.
  • the I D /I G ratio increased with increase in MWCNT: BP ratio (FIG. 2B).
  • FIG. 2B shows the bulk electrical resistivity of the MWCNT films as a function of MWCNT: BP ratio. Pristine MWCNT coatings had a resistivity of 29.45 ⁇ -cm. Adding BP
  • MWCNT:BP to samples lead to an initial increased in sheet resistivity to 35.3 ⁇ -cm for 1 : 1 (MWCNT:BP) mass ratios and reduction thereafter in sheet resistivity from to 29.2 ⁇ -cm for 1 :4 (MWCNT:BP) mass ratios.
  • MWCNT MWCNT to benzoyl peroxide (BP) mass ratio of 1 :4
  • BP benzoyl peroxide
  • AFM specimen discs Ted Pella of 15mm diameter, which can stick firmly to the magnetic triboindenter base, were coated with either MWCNT or crosslinked MWCNT and mounted into the indenter. After careful analysis of the disks under the imaging system of the triboindenter, points of indentation were selected at a distance no less than 100 ⁇ away from each other.
  • the imaging system of the triboindenter consisted of an objective of
  • magnification 10X 10X and an end zooming lens of magnification 2X.
  • a further zoom of 5X magnification was used to decide the final selection of indentation points through the special electronically controlled magnification of the triboindenter.
  • Samples were indented 7 times to determine elastic modulus (Er) and material hardness (H).
  • Er elastic modulus
  • H material hardness
  • Each indentation further comprised of 9 sub-indents in a 3 x 3 pattern and thus, the total number of indents each sample were 63. Due to the porous nature of the coatmgs, mdents resulting in outlier points were removed individually from each 3*3 indent.
  • the nanoindentation protocol yielded the values of elastic modulus (Er) and hardness (H) of the films, and are summarized in Table 1.
  • Representative force- displacement curves for the chemically-crosslinked MWCNT and pristine MWCNT films are shown in FIG. 8. Data is reported in mean ( ⁇ ), median (mdn.), standard deviation (S.D.) and interquartile range (i.q.r.).
  • the crosslinked MWCNT films also exhibited statistically significant
  • Crosslinked MWCNT films (1:4 of MWCNT:BP) were also assessed for human adipose derived stem cell (ADSC), murine preosteoblast (MC3T3) proliferation and cytotoxicity. Proliferation and cellularity were assessed by measuring mitochondrial activity on cells adhered to the MWCNT films and control glass coverslips. Day 1 cell attachment of ADSCs on MWCNT scaffolds was approximately the same as the control group, as shown in FIG. 9A, however, less initial attachment (p ⁇ 0.01) was observed for MC3T3 cells, as shown in FIG. 9B.
  • ADSC human adipose derived stem cell
  • M3T3T3T3 murine preosteoblast
  • both ADSCs and MC3T3 cells proliferate slower (p ⁇ 0.05) than the control samples, as shown in both FIGs. 6A and 6B.
  • Cytotoxicity measured by the release of LDH by compromised cell membranes, showed little to no cell death for ADSCs and MC3T3 cells at Day 3 and Day 5 timepoints.
  • these assays also suggest lower proliferation as the LDH release is decreasing and negative in values over at Day 3 and Day 5 for MC3T3 cells, as shown in FIG. 9D, and at Day 5 for ADSCs, as shown in FIG. 9C.
  • FIG. 9E illustrates the cell death on crosslinked MWCNT substrates.
  • the results are normalized to a positive control of 100% dead cells by using an LDH assay lysis buffer.
  • the ADSCs grown on coverslips released approximately 35% and 45% of LDH at days 1 and 3 as compared to the positive control while the cells on the crosslinked MWCNT substrates released approximately 50% and 43% LDH at days 1 and 3 with no statistical differences.
  • a statistical increase by 10% (p ⁇ 0.01) in LDH release was observed at day 5 timepoint LDH assay (FIG. 9B). This also corresponds to the timepoint where cell proliferation increased as observed by the MTS assay.
  • LDH cytotoxicity assay indicated that cells remained comparably viable on the MWCNT substrates and the coverslip controls at days 1 and 3.
  • the increase in LDH release at day 5 could be attributed to one of two factors: 1) an increase in basal LDH release for the increasing ADSC proliferation on crosslinked MWCNT substrates or 2) increasing cell death as the cells were in critical density without media changes for 5 days. The latter may be less likely because an increase in LDH release for ADSCs on glass coverslips was not observed.
  • Cell staining and immunofluorescence was performed on ADSCs grown on coverslips and MWCNT films grown for 5 days.
  • Cellular proliferation marker, Ki-67 was used to evaluate if the ADSC were still dividing or they entered a Go resting phase.
  • Ki-67 expression was observed through the cell cytoplasm and nucleus for glass coverslips (controls, FIG. 10A and FIG. 10B) and MWCNT (FIG. IOC and FIG. 10D) coated on glass coverslip substrates. While glass coverslips had a more even biaxial growth pattern, as shown in FIGs. 10A and 10B, longer uniaxial cytoplasmic elongation was observed on the MWCNT films than glass coverslips, as shown in FIGs. IOC and 10D. Immunohistochemistry analysis in FIGs. 10A-10D also showed cell spreading and proliferation on the MWCNT mats and provided further evidence that these mats did not affect the various phases of cell growth cycle.
  • FIGs. 1 1 A-l IF The cytoplasmic prolongations were also corroborated by SEM, FIGs. 1 1 A-l IF. Interactions with the crosslinked nanotube bundles and cell prolongations from the circled areas of FIG. 11A, and FIG. 11C show 'wrapping' form of cell adhesion (magnified in FIGs. 1 IB and 1 ID respectively).
  • the Hoechst 33342 stains indicated that dsDNA was confined within the cell in the nucleus. Together the stains provided surrogate confirmation of live cells well spread on the glass coverslips (FIG. 12A) and MWCNT substrates (FIGs. 12B and 12C).
  • the present carbon nanomaterial films showed relatively high orders of interconnectivity and crosslinking in SEM and TEM images as well as Raman spectroscopy. Increased electrical conductivity was observed when increasing the concentration of crosslinking reagent. Further, cytocompatibility analysis towards MC3T3-E1 osteoblasts and ADSCs were alive and proliferating on crosslinked MWCNT substrates.
  • the disclosed method creates chemical bonds to adjoin sp 2 -hybridized nanomaterials while substantially maintaining their architectural features and electrical conductivity.
  • This method and resultant carbon film can be useful in many fields, including but not limited to fields where carbon nanotubes and graphene thin films are used such as electronics and biomedical applications.
  • single walled carbon nanotubes were dispersed in ethyl acetate with benzoyl peroxide and one of three crosslinkers (ethylene diacrylate, methylene bisacrylamide, and divinyl benzene).
  • concentration of the nanomaterials to solvent was lmg/mL.
  • the mass ratio for the nanoparticle (SWNCT), free radical initiator (benzoyl peroxide), and crosslinker in the solution was 1 : 1 :2 respectively.
  • the mixture was spray coated, as discussed in Examples 1 and 2 above, onto titanium discs (12mm diameter) and heated to 120°C by an automated ultrasonic spray coating system. After heating, the nanomaterial films were characterized by Raman spectroscopy and atomic force microscopy (AFM).
  • FIG. 14 includes AFM images of SWCNT crosslinked with varying crosslinking agents, including from the left of FIG. 14 to the right, divinyl benzene, ethylene diacrylate and methylene bisacrylamide.
  • crosslinking occurs in films created from mixtures of carbon nanomaterials (SWCNT in this example), an initiator (BP in this example) and crosslinkers.

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Abstract

Cette invention concerne des procédés de formation d'un film de carbone et des substrats, sur lesquels les films de carbone peuvent être formés. Le procédé de formation d'un film de carbone comprend les étapes de mélange d'un nanomatériau de carbone avec un amorceur pour former un mélange de nanomatériau et amorceur, le placement du mélange sur une surface de substrat et le maintien du mélange et du substrat à une température supérieure à la température ambiante pendant une certaine période de temps pour former le film. Le substrat comprend un film de carbone formé sur une surface du substrat, le substrat étant thermiquement stable jusqu'à environ 120°C.
PCT/US2015/028524 2014-04-30 2015-04-30 Films et procédés de formation de films à base de structures en un nanomatériau de carbone Ceased WO2015168411A1 (fr)

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CN110312680A (zh) * 2017-01-11 2019-10-08 通用电气(Ge)贝克休斯有限责任公司 包括交联的碳纳米结构的薄膜衬底和相关方法
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US20200139402A1 (en) * 2012-04-09 2020-05-07 Nanocomp Technologies, Inc. Nanotube material having conductive deposits to increase conductivity
CN110312680A (zh) * 2017-01-11 2019-10-08 通用电气(Ge)贝克休斯有限责任公司 包括交联的碳纳米结构的薄膜衬底和相关方法
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CN107785166A (zh) * 2017-11-08 2018-03-09 电子科技大学 一种具有单轴各向异性的稀磁合金的制备方法
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CN116904984A (zh) * 2023-07-06 2023-10-20 广东中科安齿生物科技有限公司 一种钛植入物及其亲水表面构建方法
CN116904984B (zh) * 2023-07-06 2025-11-18 广东中科安齿生物科技有限公司 一种钛植入物及其亲水表面构建方法

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