FABRICATION AND APPLICATION OF NANOFIBER RIBBONS AND SHEETS AND TWISTED AND NON-TWISTED NANOFIBER YARNS
The present invention is directed to nanofiber yarns, ribbons, and sheets; to methods of making said yarns, ribbons, and sheets; and to applications of said yarns, ribbons, and sheets. In some embodiments, the nanotube yarns, ribbons, and sheets comprise carbon nanotubes. Particularly, such carbon nanotube yarns of the present invention provide unique properties and property combinations such as extreme toughness, resistance to failure at knots, high electrical and thermal conductivities, high absorption of energy that occurs reversibly, up to 13% strain-to-failure compared with the few percent strain-to-failure of other fibers with similar toughness, very high resistance to creep, retention of strength even when heated in air at 450° C. for one hour, and very high radiation and UV resistance, even when irradiated in air. Furthermore these nanotube yarns can be spun as one micron diameter yarns and plied at will to make two-fold, four-fold, and higher fold yarns. Additional embodiments provide for the spinning of nanofiber sheets having arbitrarily large widths. In still additional embodiments, the present invention is directed to applications and devices that utilize and/or comprise the nanofiber yarns, ribbons, and sheets of the present invention.
1 - 469 . (canceled)
470 . A process for continuously producing a nanofiber sheet, ribbon, or yarn, the process comprising:
(a) synthesizing a nanofiber forest in a furnace growth region on a substrate, wherein the nanofiber forest comprises a parallel array of nanofibers; and
(b) drawing said nanofibers from the nanofiber forest to form a primary assembly that is a sheet, ribbon or yarn, wherein the substrate continuously moves from the furnace growth region into a region where the nanofibers in the forest are drawn.
471 . The process of claim 470 , wherein the drawing occurs without twisting when the primary assembly is a ribbon or a sheet and drawing includes twisting when the primary assembly is a yarn.
472 . The process of claim 470 , wherein the substrate is in motion with respect to the furnace growth region.
473 . The process of claim 470 , wherein the substrate is flexible.
474 . The process of claim 470 , wherein the substrate is a flexible belt or is attached to a moving belt.
475 . The process of claim 470 , wherein the substrate on which the nanofiber forest is synthesized is a drum and the nanofibers are drawn from the drum.
476 . The process of claim 470 further comprising depositing the primary assembly on a second substrate.
477 . The process of claim 476 , wherein the step of depositing comprises wrapping the primary assembly on the second substrate.
478 . The process of claim 470 , wherein the drawing of said nanofibers produces a nanofiber ribbon, and wherein the nanofiber ribbon is laminated to a second nanofiber ribbon to form a nanofiber sheet.
479 . The process of claim 478 , wherein the step of laminating comprises involves a laminating means selected from the group consisting of chemical binding agent, an electron beam, thermal treatment, an ion beam, radio frequency irradiation, microwave irradiation, and combinations thereof.
480 . The process of claim 470 , wherein the nanofiber forest is synthesized by chemical vapor deposition.
481 . The process of claim 470 , wherein said nanofiber forest is densified by imbibing a liquid comprising a volatile component and subsequently evaporating the volatile component of the liquid.
482 . The process of claim 470 , wherein said nanofibers are selected from the group consisting of imogolite nanofibers; carbon nanotubes; doped carbon nanotubes; SiC nanofibers; MgB 2 nanofibers; carbon doped MgB 2 nanofibers; Bi nanofibers; nanofibers of binary group III-V elements; Si nanofibers; ZnO nanofibers; selenium nanofibers; nanofibers that are fluorinated; nanofibers that are compounds of Mo, S, and I; and combinations thereof.
483 . The process of claim 470 , wherein the nanofibers comprise carbon nanotubes.
484 . A process for continuously producing a nanofiber sheet, ribbon, or yarn, the process comprising:
(a) synthesizing a nanofiber forest in a furnace growth region on a substrate, wherein the nanofiber forest comprises a parallel array of nanofibers having a degree of inter-fiber connectivity;
(b) drawing said nanofibers from the nanofiber forest to form a primary assembly that is a sheet, ribbon or yarn, wherein the substrate continuously moves from the furnace growth region into a region where the nanofibers in the forest are drawn; and
(c) infiltrating the primary assembly with a liquid and subsequently evaporating the liquid from the primary assembly, wherein the infiltration and evaporation at least partially densifies the primary assembly.
485 . The process of claim 484 , wherein said infiltration with the liquid comprises a method selected from the group consisting of vapor condensation, imbibing a liquid, exposure to a liquid aerosol, and combinations thereof.
486 . The process of claim 484 , wherein the liquid comprises a substance selected from the group consisting of water, acetone, ethanol, methanol, isopropyl alcohol, toluene, chloroform, chlorobenzene and combinations thereof.
487 . The process of claim 484 , wherein the substrate is flexible.
488 . The process of claim 484 , wherein the substrate is a flexible belt or is attached to a moving belt.
489 . The process of claim 484 , wherein the substrate is a drum.
490 . The process of claim 484 , wherein drawing occurs without twisting when the primary assembly is a ribbon or a sheet and drawing includes twisting when the primary assembly is a yarn.
491 . The process of claim 484 , wherein the nanofibers comprise carbon nanotubes.