Anisotropic buckypaper through shear-induced mechanical alignment of carbon nanotubes in water

A simple method for aligning nanotubes in buckypaper with a modified Taylor–Couette system is reported. Using shear forces produced by a rotating cylinder to orient multi-walled carbon nanotubes in a surfactant-assisted aqueous dispersion, the suspended nanotubes are simultaneously aligned and filtered. The resulting buckypaper is composed of nanotubes with preferential orientation in the direction of flow and possesses anisotropic electrical and mechanical properties, which are both enhanced parallel to the direction of orientation. The technique presented here requires no specialized equipment and can be implemented with any type of carbon nanotube synthesized by any method. Furthermore, the size of the buckypaper sheets can be easily increased by adjusting the length and diameter of the cylinders in the setup, offering the possibility for low-cost production of large quantities of oriented buckypaper.