Process for producing integral graphene films from functionalized graphene sheets
Provided is a process for producing an integral graphene film, comprising: (a) preparing a graphene dispersion having chemically functionalized graphene sheets dispersed in a fluid medium wherein the graphene sheets contain chemical functional groups attached thereto; (b) dispensing and depositing a wet film of the graphene dispersion onto a supporting substrate, wherein the dispensing and depositing procedure includes mechanical shear stress-induced alignment of the graphene sheets along a film planar direction, and partially or completely removing the fluid medium to form a relatively dried film comprising aligned chemically functionally graphene sheets; and (c) using heat, electromagnetic waves, UV light, or high-energy radiation to induce chemical reactions or chemical bonding between chemical functional groups attached to adjacent chemically functionalized graphene sheets to form the integral graphene film. The film after step (b) or (c) may be further compressed to increase the degree of graphene sheet orientation in the integral graphene film.
1. A process for producing an integral graphene film from chemically functionalized graphene sheets, said process comprising:
(a) preparing a graphene dispersion having chemically functionalized graphene sheets dispersed in a liquid medium wherein said chemically functionalized graphene sheets comprise chemical functional groups attached thereto and a non-carbon element content of 0.1% to 47% by weight;
(b) dispensing and depositing a wet film of said graphene dispersion onto a supporting substrate via high-rate or high-intensity spraying, or extrusion plus high-rate wiping, wherein said dispensing and depositing procedure includes mechanical shear stress-induced alignment of said chemically functionalized graphene sheets along a film planar direction, and partially or completely removing said liquid medium from said wet film to form a dried graphene film comprising aligned chemically functionalized graphene sheets; and
(c) using high-energy radiation to induce chemical reactions or chemical bonding between chemical functional groups attached to adjacent chemically functionalized graphene sheets in said dried graphene film to form said integral graphene film, wherein said integral graphene film comprises chemically functionalized graphene sheets that are chemically bonded or interconnected with one another having an inter-planar spacing d 002 from 0.36 nm to 1.5 nm as determined by X-ray diffraction and a non-carbon element content of 0.1% to 47% by weight, wherein said functionalized graphene sheets are substantially parallel to one another and parallel to a planar direction of said integral graphene film and said integral graphene film has a length from 1 cm to 10,000 m, a width from 1 cm to 5 m, a thickness from 2 nm to 500 μm, and a physical density from 1.5 to 2.2 g/cm 3 , wherein said integral graphene film has a degree of graphene plane orientation from 87% to 99%,
wherein said chemically functionalized graphene sheets contain a chemical functional group selected from the group consisting of alkyl or aryl silane, alkyl or aralkyl group, hydroxyl group, carboxyl group, carboxylic group, amine group, sulfonate group, aldehydic group, quinoidal, fluorocarbon, derivatives thereof, and combinations thereof; wherein said chemically functionalized graphene sheets contain a chemical functional group selected from an oxygenated group consisting of hydroxyl, peroxide, ether, keto, aldehyde, and combinations thereof; or wherein said chemically functionalized graphene sheets contain a chemical functional group selected from the group consisting of 10,12-pentacosadiyn-1-ol, hydroiodic acid, 1-pyrenebutyric acid N-hydroxysuccinimide ester, 1-aminopyrene, derivatives thereof, and combinations thereof.
2. The process of claim 1 , wherein said inter-plane spacing d 002 is from 0.4 nm to 1.2 nm, the non-carbon element content is from 1% to 20%, or physical density from 2.0 to 2.15 g/cm 3 .
3. The process of claim 1 , wherein said integral graphene film has a thermal conductivity from 200 to 1,600 W/mK or an electrical conductivity from 600 to 15,000 S/cm.
4. The process of claim 1 , wherein said integral graphene film has a Young's modulus from 20 GPa to 200 GPa, or a tensile strength from 1.0 GPa to 3.5 G Pa.
5. The process of claim 1 , further comprising a step of compressing said integral graphene film to increase a degree of graphene sheet orientation and physical density, and to improve contact between chemically functionalized graphene sheets.
6. The process of claim 1 , further comprising a step of reducing said non-carbon content to less than 20% by weight using chemical, thermal, UV, or radiation means.
7. A process for producing an integral graphene film from graphene sheets, said process comprising:
(a) preparing a graphene dispersion having un-functionalized graphene sheets dispersed in a liquid medium;
(b) dispensing and depositing a wet film of said graphene dispersion onto a supporting substrate via high-rate or high-intensity spraying, or extrusion plus high-rate wiping, wherein said dispensing and depositing procedure includes mechanical shear stress-induced alignment of said un-functionalized graphene sheets along a film planar direction, and partially or completely removing said liquid medium from said film to form a dried graphene film comprising aligned graphene sheets;
(c) bringing said dried graphene film in contact with a chemical functionalizing agent so as to produce a film of chemically functionalized graphene sheets having chemical functional groups attached thereto and a non-carbon element content of 0.1% to 47% by weight; and
(d) using high-energy radiation to induce chemical reactions or chemical bonding between chemical functional groups attached to adjacent chemically functionalized graphene sheets to form said integral graphene film, wherein said integral graphene film comprises chemically functionalized graphene sheets that are chemically bonded or interconnected with one another having an inter-planar spacing d 002 from 0.36 nm to 1.5 nm as determined by X-ray diffraction and a non-carbon element content of 0.1% to 47% by weight, wherein said functionalized graphene sheets are substantially parallel to one another and parallel to a planar direction of said integral graphene film and said integral graphene film has a length from 1 cm to 10,000 m, a width from 1 cm to 5 m, a thickness from 10 nm to 500 μm, and a physical density from 1.5 to 2.2 g/cm 3 , wherein said integral graphene film has a degree of graphene plane orientation from 87% to 99%, wherein said chemically functionalized graphene sheets contain a chemical functional group selected from the group consisting of alkyl or aryl silane, alkyl or aralkyl group, hydroxyl group, carboxyl group, carboxylic group, amine group, sulfonate group, aldehydic group, quinoidal, fluorocarbon, derivatives thereof, and combinations thereof; wherein said chemically functionalized graphene sheets contain a chemical functional group selected from an oxygenated group consisting of hydroxyl, peroxide, ether, keto, aldehyde, and combinations thereof; or wherein said chemically functionalized graphene sheets contain a chemical functional group selected from the group consisting of 10,12-pentacosadiyn-1-ol, hydroiodic acid, 1-pyrenebutyric acid N-hydroxysuccinimide ester, 1-aminopyrene, derivatives thereof, and combinations thereof.
8. The process of claim 7 , wherein said chemically functionalized graphene sheets further contain a chemical functional group selected from a derivative of an azide compound selected from the group consisting of 2-azidoethanol, 3-azidopropan-1-amine, 4-(2-azidoethoxy)-4-oxobutanoic acid, 2-azidoethyl-2-bromo-2-methylpropanoate, chlorocarbonate, azidocarbonate, dichlorocarbene, carbene, aryne, nitrene, (R—)-oxycarbonyl nitrenes, where R=any one of the following groups,
and combinations thereof.
9. The process of claim 7 , wherein said chemically functionalized graphene sheets further contain a chemical functional group selected from the group consisting of —SO 3 H, —COOH, —NH 2 , —OH, —R′CHOH, —CHO, —CN, —COCl, halide, —COSH, —SH, —COOR′, —SR′, —SiR′ 3 , —Si(—OR′—) y R′ 3 —y, —Si(—O—SiR′ 2 —)OR′, —R″, Li, AlR′ 2 , Hg—X, TlZ 2 and Mg—X; wherein y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, or aralkyl, cycloaryl, or poly(alkylether), R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl, fluoroaralkyl or cycloaryl, X is halide, and Z is carboxylate or trifluoroacetate, derivatives thereof, and combinations thereof.
10. The process of claim 7 , wherein said chemically functionalized graphene sheets further contain a chemical functional group selected from the group consisting of amidoamines, polyamides, aliphatic amines, modified aliphatic amines, cycloaliphatic amines, aromatic amines, anhydrides, ketimines, diethylenetriamine (DETA), triethylene-tetramine (TETA), tetraethylene-pentamine (TEPA), polyethylene polyamine, polyamine epoxy adduct, phenolic hardener, non-brominated curing agent, non-amine curatives, derivatives thereof, and combinations thereof.
11. The process claim 7 , wherein said chemically functionalized graphene sheets further contain a chemical functional group selected from OY, NHY, O═C—OY, P═C—NR′Y, O═C—SY, O═C—Y, —CR′1—OY, N′Y or C′Y, a derivative thereof, or a combination thereof, and Y is a functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—NR′ 2 , R′SH, R′CHO, R′CN, R′X, R′N + (R′) 3 X″, R′SiR′ 3 , R′Si(—OR′—) y R′ 3-y , R′Si(—O—SiR′ 2 —)OR′, R′—R″, R′—N—CO, (C 2 H 4 O—) w H, (—C 3 H 6 O—) w H, (—C 2 H 4 O) w —R′, (C 3 H 6 O) w —R′, R′, and w is an integer greater than one and less than 200.
12. The process of claim 7 , wherein said integral graphene film has a thermal conductivity from 350 to 1,600 W/mK or an electrical conductivity from 1,000 to 15,000 S/cm.
13. The process of claim 7 , wherein said integral graphene film has a Young's modulus from 20 GPa to 130 GPa or a tensile strength from 1.0 GPa to 3.0 GPa.
14. The process of claim 7 , further comprising a step of compressing said integral graphene film to increase a degree of graphene sheet orientation and physical density, and to improve contact between chemically functionalized graphene sheets.
15. The process of claim 7 , further comprising a step of reducing said non-carbon content to less than 20% by weight using chemical, thermal, UV, or radiation means.