Remarkable Electrothermal Behaviors and Performance Stability of Carbon Nanotube Films Densifying with Various Methods

In this study, carbon nanotube films, densifying with ethanol/water, acetone/water, acetic acid/water, sulfuric acid/water with a volume rate of 4:1 and following the rolling process, were manufactured. Afterward, the electrothermal, mechanical properties, and performance stability of these carbon nanotube films were investigated, along with mechanism analysis. Based on the investigations, the ability of rapid electrothermal response within 5 seconds, the higher steady-state temperature of above 120~160^oC at a low input voltage of 5V, excellent cycling stability of electrical heating is reported by the aforementioned methods, revealing better outcome compared with previous papers of congeneric carbon nanotube films. The electrothermal and mechanical properties of treated carbon nanotube films were superior to carbon nanotube film pressed from carbon nanotube aerosol, and the best outcomes could be synchronously achieved at an immersion of 0.5h in solvents and rolling. The consequences, which are attributable to treatments by the first three mixed solvents as well as rolling, were similar, however, the electrical and electrothermal properties of carbon nanotube film treated with sulfuric acid/water and rolling were significantly improved compared with others due to p-type doping and purification, which could enhance the electrical conductivity of carbon nanotube film, while the mechanical property was not degraded compared to films treated by other ways. Particularly, electrical and mechanical properties of carbon nanotube films were unchanged through repeated electrical heating owing to the stability of their structure and morphology, which contributed to exceedingly stable electrothermal property and established a foundation for application as a heater with long-term stability. Lastly, the mechanism concerning the performance stability of electrical heating film has been proposed.