Variable Volume Fraction Aligned CNT and Nanocomposite Fabrication Using Mechanical Densification

Generally, the present invention provides methods for the production of materials comprising a plurality of nanostructures such as nanotubes (e.g., carbon nanotubes) and related articles. The plurality of nanostructures may be provided such that their long axes are substantially aligned and, in some cases, continuous from end to end of the sample. For example, in some cases, the nanostructures may be fabricated by uniformly growing the nanostructures on the surface of a substrate, such that the long axes are aligned and non-parallel to the substrate surface. The nanostructures may be, in some instances, substantially perpendicular to the substrate surface. In one set of embodiments, a force with a component normal to the long axes of the nanostructures may be applied to the substantially aligned nanostructures. The application of a force may result in a material comprising a relatively high volume fraction or mass density of nanostructures. In some instances, the application of a force may result in a material comprising relatively closely-spaced nanostructures. The materials described herein may be further processed for use in various applications, such as composite materials (e.g., nanocomposites). For example, a set of aligned nanostructures may be formed, and, after the application of a force, transferred, either in bulk or to another surface, and combined with another material (e.g., to form a nanocomposite) to enhance the properties of the material.