Process for producing integral graphene films from functionalized graphene sheets

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 d002 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/cm3, 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.