Fabrication and application of nanofiber ribbons and sheets and twisted and non-twisted nanofiber yarns

A process for producing a nanofiber ribbon or sheet from a nanofiber forest that comprises the following steps:

• (a) producing a nanofiber forest comprising nanofibers, wherein the nanofiber forest is suitable for drawing ribbons or sheets from the nanofiber forest, wherein the ribbon or sheet would be at least about one millimeter in width, and wherein the nanofiber forest has a sidewall;
• (b) connecting an attachment to the sidewall or near the sidewall of the nanofiber forest;
• and
• (c) drawing the nanofiber ribbon or sheet from the nanofiber forest by drawing upon the attachment.

A process comprises the following steps:

• (a) producing a carbon nanotube forest comprising nanotubes, wherein the carbon nanotube forest is suitable for drawing ribbons or sheets from the carbon nanotube forest, wherein the ribbon or sheet would be at least about one millimeter in width and wherein the carbon nanotube forest has a sidewall;
• (b) connecting an attachment to the sidewall or near the sidewall of the carbon nanotube forest;
• (c) drawing the ribbon or sheet from the carbon nanotube forest by drawing upon the attachment, wherein the ribbon or sheet is a highly oriented aerogel ribbon or sheet;
• and
• (d) infiltrating the sheet or ribbon with a liquid and subsequently evaporating the liquid from the sheet or ribbon, wherein the infiltration and evaporation at least partially densifies the sheet or ribbon and forms a densified sheet or ribbon.

A process of producing a nanofiber ribbon or sheet comprising the following steps:

• (a) arranging nanofibers to provide a parallel nanofiber array having a degree of inter-fiber connectivity within the nanofiber array;
• (b) drawing said nanofibers from the nanofiber array as a ribbon or sheet without twisting the ribbon or sheet;
• and
• (c) depositing said ribbon or sheet on a substrate.