Preparation of carbon nanotube film with high alignment and elevated density

Carbon nanotube (CNT) film with high alignment and elevated densities was prepared by taking CNT ribbons as component unit fabricated by floating catalyst chemical vapor deposition (FCCVD) method. The as prepared film showed good alignment but low density, however, the density of the CNT film increased by 109% after the rolling treatment due to elimination of pores and gaps in the films. The alignment measured by the ratio I_G∥/I_G⊥ obtained from polarized Raman scattering measurements increased from 1.44 to 1.90. The tensile strengths of the CNT film were recorded respectively as 765 ± 15 MPa and 184 ± 58 MPa in parallel and perpendicular directions to CNT ribbons alignment, and the corresponding electrical conductivities were (1.65 ± 0.15) × 10⁵ S/m and (1.04 ± 0.10) × 10⁵ S/m. These findings indicated that combination of FCCVD with the rolling treatment led to highly aligned CNT film with elevated densities, and thus improved tensile strengths and electrical conductivities.