Abstract: Nanotube structures and methods for forming nanotube structures are disclosed. The methods include forming nanotubes such that they are associated with a surface of a substrate and compressing at least a portion of the nanotubes. In some embodiments, the nanotubes may be dimensionally constrained in one direction while being compressed in another direction. Compressing at least a portion of the nanotubes may comprise stamping an impression into a surface of the nanotubes, at least a portion of which is retained when the stamp is removed. In some embodiments, the nanotubes may be aligned with respect to one another and to the surface of the substrate and may extend in a direction that is, for example, normal to the substrate.

Abstract: Methods for forming freestanding objects primarily comprising aligned carbon nanotubes, as well as the objects made by these methods, are provided. Arrays of generally aligned carbon nanotubes are first synthesized on a substrate then released from the substrate and densified, maintaining the aligned arrangement. These densified arrays can take the form of thin strips which can be joined together, for example by lamination, to form larger objects of arbitrary size. These objects can be further cut or otherwise machined to desired dimensions and shapes. Release from the substrate can be accomplished mechanically, such as by shearing, or chemically, such as by etching. Densification can be accomplished, for example, through compaction or by taking advantage of capillary forces. In the latter case, an array is first wetted with a fluid and then dried. As the fluid is removed, capillary forces draw the nanotubes closer together.