JP-2026074405-A - Method for producing a forest of ultra-long carbon nanotubes

Abstract

[Challenge] The challenge is to produce a forest of ultra-long carbon nanotubes. [Solution] A method for producing an ultra-long carbonanotube forest, characterized in that an electric furnace is placed around the outer circumference of a quartz tube having a reaction substrate coated with an Fe catalyst at its lower part, and a neptilizer device is placed in a vertical thermal CVD apparatus with a Cu coil at the bottom of the electric furnace, a mixture of ferrocene and ethanol is sprayed from the neptilizer device into the quartz tube to synthesize carbonanotubes on the reaction substrate, and then current is passed through the Cu coil to generate magnetic field lines, thereby guiding and growing the synthesized carbonanotubes in the direction of the magnetic field lines. [Selection Diagram] Figure 1

Inventors

• 張 剣輝
• 加藤 正明
• 于 暁玲

Assignees

• グローバルファクトリー株式会社

Dates

Publication Date

20260507

Application Date

20241021

Claims (1)

1. A method for producing an ultra-long carbonanotube forest, characterized by: a vertical thermal CVD apparatus having a reaction substrate coated with an Fe catalyst at its lower part, an electric furnace placed around the outer circumference of the quartz tube, and a Cu coil at the bottom of the electric furnace; a neptilator device placed in the apparatus; a mixture of ferrocene and ethanol sprayed from the neptilator device into the quartz tube to synthesize carbonanotubes on the reaction substrate; and further energizing the Cu coil to generate magnetic field lines, thereby guiding and growing the synthesized carbonanotubes in the direction of the magnetic field lines.

Description

This invention relates to a method for producing a forest of ultra-long carbon nanotubes (CNTs) usable for use in space elevator cables. The principle of a space elevator is relatively simple. One end of a long cable is fixed to Earth, and the other end to a counterweight in geostationary orbit (such as a large space station). The interaction of gravity and centrifugal force maintains tension in the cable. Using electricity generated by converting solar or laser energy, the space elevator can move up and down along this cable. Because this cable is subjected to both gravity and centrifugal force, the material it uses is the biggest challenge. Elevators used in everyday life are made with steel cables, and steel cables are also used over long distances in skyscrapers and bridges. However, for even longer distances, the cable will break under its own weight. Therefore, to realize a space elevator, a new material is needed that is far stronger and lighter than conventional materials. This cable is approximately 100,000 kilometers long, and such a long structure requires sufficient tensile strength to support it. Carbon nanotubes (CNTs) are among the toughest materials ever discovered, and their macroscopic strength and toughness surpass those of currently widely used materials such as carbon fibers and aramids. To realize a space elevator, the cable material needs to have a strength of 7.5 GPa/(g/ cm³ ) or more per unit mass, and until now, only carbon nanotubes (CNTs) can meet this requirement. The tensile strength of CNTs exceeds 100 GPa, and if we estimate its density to be approximately 1.6 g/ cm³ , its specific strength becomes 62.5 GPa/(g/ cm³ ) or more, far exceeding the specific strength required for the material needed for a space elevator. Japanese Patent Publication No. 2019-151515Special Publication No. 2019-504838Re-table 2016/208558 Researcher Koji Sugime and Researcher Tsubasa Inoue, "Topic: Successful Extension of Carbon Nanotubes" Press Release, Research Highlights, Research Activities, Tue, 27, Oct 2020 Image of a vertical thermal CVD apparatus.A long-format diagram illustrating the mechanism of a CNT forest.An access diagram illustrating the creation of a long-form CNTs forest.SEM and TEM images of a long CNT forest.A Raman plot of a long CNT forest.An image illustrating a space elevator. A method for producing an ultra-long carbon nanotube forest, characterized by: placing an electric furnace around the outer circumference of a quartz tube having a reaction substrate coated with an Fe catalyst at its lower part; placing a neptilizer device in a vertical thermal CVD apparatus with a Cu coil at the bottom of the electric furnace; spraying a mixture of ferrocene and ethanol from the neptilizer into the quartz tube to synthesize carbon nanotubes on the reaction substrate; and further energizing the Cu coil to generate magnetic field lines, thereby guiding and growing the synthesized carbon nanotubes in the direction of the magnetic field lines. In summary, the method for producing ultra-long carbon nanotube forests according to the present invention shortens the growth time, enabling more efficient synthesis of ultra-long CNTs. This expands the applications of carbon nanotubes (CNTs) to fields such as electronic devices, composite materials, and the aerospace industry.