Solvent-Tunable Microstructures of Aligned Carbon Nanotube Films

Solvent wetting is an efficient way to densify carbon nanotube (CNT) assembly structures. Besides the polarity that determines the densification level, the solvent's volatility is found to affect the assembly structure at the micrometer scale. A high volatile solvent like acetone can cause CNTs to simultaneously establish close contact at many intersecting points, and thus creates a strong network structure. This networking ability results in high plasticity for the resulting CNT assembly films. On the other hand, a low volatile solvent like N,N-dimethylformamide reduces the density of connection points due to nonlocalized CNT densification. The networking effect has a strong influence on the film's tensile property by the virtue of the improved plasticity. The acetone-densified CNT film (up to 2.32-3.19 GPa) is about 20% stronger than that densified by ethanol.