Abstract: A carbon nanostructure that is free of a growth substrate can include a plurality of carbon nanotubes that are branched, crosslinked, and share common walls with one another. The carbon nanostructure can be released from a growth substrate in the form of a flake material. Optionally, the carbon nanotubes of the carbon nanostructure can be coated, such as with a polymer, or a filler material can be present within the porosity of the carbon nanostructure. Methods for forming a carbon nanostructure that is free of a growth substrate can include providing a carbon nanostructure adhered to a growth substrate, and removing the carbon nanostructure from the growth substrate to form a carbon nanostructure that is free of the growth substrate. Various techniques can be used to affect removal of the carbon nanostructure from the growth substrate. Isolation of the carbon nanostructure can further employ various wet and/or dry separation techniques.