Densifying effect on the properties of carbon nanotube film

As a kind of two-dimensional carbon nanotube (CNT) macroscopic material, CNT film fabricated from the chemical vapor deposition (CVD)-grown spinnable CNT array generally has better orientation and less impurities, could transfer the properties of CNT efficiently, possessing great potential in mechanical, electrical, thermal and optical application. In this paper, continuous single layer CNT sheet was drawn from super-aligned spinnable CNT array and wound by a rotating mandrel to fabricate pure CNT film. By controlling the main fabricating process parameters, the densifying degree and tensile properties of pure CNT film were adjusted, meanwhile the effects of densifying process parameters on the mechanical properties of CNT film were also studied. Based on these, optimized densifying assembling process conditions which would be beneficial to aligning and dense packing of CNTs with less-porosity were presented. Besides, the influences of different solvent densifying approaches on CNT film's structure and tensile properties were also discussed. It is found that comparing with the previous reported spray-winding densifying method, an innovative solvent evaporation-induced densifying method could efficiently avoid the air-disturbance during the fabrication, assemble CNTs into much denser structure with good flexibility, better alignment, and increase the tensile properties and electrical conductivity significantly. As a convenient approach, it is considered to provide a reasonable optimized fabrication route for high performance CNT films.