A method to manufacture enhanced carbon nanotube rope and enhanced carbon nanotubes assemblies has been developed by Seoul National University (SNU) chemists.
Carbon nanotubes (CNT) are one-dimensional nano-materials that exhibit unique electrical properties. Such unique properties allow them to be potentially useful in various fields such as nanotechnology, electronics, optics, etc. For example, CNTs are widely used in micro devices such as integrated circuits, electrical connectors used in semiconductor chips in computers, batteries, high-frequency antennas, scanning tunnel microscopes, atomic force microscopes, scanning probe microscopes, etc.
However, it is difficult to control an individual CNT due to its nano-size geometry and powder form. Thus, macroscopic applications relying on CNTs have limitations in terms of marketability and commercial feasibility. In order to solve this problem, significant research efforts are being made with respect to the formation of macroscopic building blocks using CNTs. Moreover, various studies have been conducted to further understand CNTs so as to expand their applications into numerous fields.
Seoul National University Research & Development Business Foundation (Seoul, KR) researchers Yong Hyup Kim and Eui Yun Jang detail novel techniques for manufacturing an enhanced CNT assembly in U.S. Patent Application 20100040529. The CNT plus transition-metal composite assembly is grown through a chemical vapor deposition process and a dip pen process.
However, it is difficult to control an individual CNT due to its nano-size geometry and powder form. Thus, macroscopic applications relying on CNTs have limitations in terms of marketability and commercial feasibility. In order to solve this problem, significant research efforts are being made with respect to the formation of macroscopic building blocks using CNTs. Moreover, various studies have been conducted to further understand CNTs so as to expand their applications into numerous fields.
Seoul National University Research & Development Business Foundation (Seoul, KR) researchers Yong Hyup Kim and Eui Yun Jang detail novel techniques for manufacturing an enhanced CNT assembly in U.S. Patent Application 20100040529. The CNT plus transition-metal composite assembly is grown through a chemical vapor deposition process and a dip pen process.
By way of an example, inventors Kim and Jang have partially succeeded in synthesizing the macroscopic one-dimensional CNT assemblies from CNT colloidal solutions via a dip-coating method. However, it was found that each of the CNTs in the assembly adhered to neighboring CNTs by a relatively weak van der Waals force. Thus, the CNT assembly was easily broken when a mechanical force was applied. As such, there still exists a need to improve the mechanical property of the CNT assembly.
In one embodiment, their method of manufacturing an enhanced CNT assembly comprises: (1) preparing a metal tip, (2) preparing a CNT plus transition-metal colloidal solution, forming a CNT plus transition-metal composite assembly by using the prepared metal tip and the CNT plus transition-metal colloidal solution, and (3) growing the CNT plus transition-metal composite assembly. The metal tip is fabricated from tungsten. The metal tip has an apex of a conical shape. The metal tip is prepared using an electrochemical etching method.
The method further includes preparing the CNT plus transition-metal colloidal solution comprises: preparing purified CNT powders and transition-metal powders; dispersing the purified CNT powders into a solvent; combining the transition-metal powders with the solvent including the purified CNT powders; and performing a sonication treatment upon the solvent including the purified CNT powders and the transition-metal powders. The solvent includes any one of water, organic solution and N,N-DMF (dimethyl formamide).
In another embodiment, a manufacturing method of an enhanced CNT assembly comprises forming a CNT composite assembly comprising CNTs and particles of a nickel transition metal, and growing the CNT composite assembly. The growth of the CNT composite assembly is facilitated by the particles of the transition metal.
In another embodiment, a manufacturing method of an enhanced CNT assembly comprises forming a CNT composite assembly comprising CNTs and particles of a nickel transition metal, and growing the CNT composite assembly. The growth of the CNT composite assembly is facilitated by the particles of the transition metal.
FIG. 3 shows photographs of one example of a manufactured tungsten tip used to manufacture enhanced carbon nanotube materials.
FIG. 6 is a picture obtained using a scanning electron microscope showing SWNT colloid distribution within meniscus. As illustrated in a box 610, CNTs are dispersed in the SWNT colloids in a disorderly fashion around the edge of the meniscus. However, CNTs are gradually aligned around the center of the meniscus, as shown in boxes 620 and 630. The aligned CNTs and Ni particles adhere together due to the van der Waals forces, thereby forming the CNT plus Ni composite assembly
FIG. 8 shows one example of an enhanced CNT manufactured by SNU’s process. In the enhanced CNT as shown, Ni particles seize CNTs, which in turn become tangled around the Ni particles. As a result, CNTs are strongly interconnected and acquire an enhanced mechanical property compared to a conventional CNT rope.
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