Carbon nanotubes were first produced in the early 1990s. They’re exactly what their name suggests – tubes of carbon created on the nanoscale. Although they’re small – thousands of times smaller than a human hair, in fact – they’re incredibly strong, and they’re also great conductors of heat and electricity. Thus, they’ve become in very high demand for researchers, many of whom are studying the incorporation of the tubes into 3D printed applications, or 3D printing the tubes themselves.
A group of South Korean researchers is working with 3D printed carbon nanotubes for the development of bendable electronic devices and wearable technology. The Korea Electrotechnology Research Institute (KERI) has developed a new technology to 3D print highly conductive multiwall carbon nanotubes, or MWNT, using liquid ink. The research is documented in a paper entitled “Three-Dimensional Printing of Highly Conductive Carbon Nanotube Microarchitectures with Fluid Ink,” which you can access here.
“Moving printed electronics to three dimensions essentially requires advanced additive manufacturing techniques yielding multifunctionality materials and high spatial resolution,” the researchers state. “Here, we report the meniscus-guided 3D printing of highly conductive multiwall carbon nanotube (MWNT) microarchitectures that exploit rapid solidification of a fluid ink meniscus formed by pulling a micronozzle.”
To achieve smooth 3D printing without any nozzle clogging, the researchers designed a polyvinylpyrrolidone-wrapped MWNT ink with uniform dispersion. According to the team, led by Seol Seung-kwon, the 3D printing technique is able to achieve a variety of microstructures with a high concentration of MWNT – up to 75 wt percent obtained through thermal post-treatment, which further strengthened the parts.
The practical applications of the 3D printed carbon nanotubes are many. In the study, the researchers demonstrated several electronic components including sensing transducers, emitters, and radio frequency inductors. The technology may also prove valuable in the manufacture of wearable electronics, including bendable electronic suits.
“Existing 3D printing technology was limited in usage,” Seol said. “This latest method would enhance the versatility of 3D printing in the making of various components needed for future wearables.”
The technique gives scientists more control over the 3D printing process and thus the ability to create more complex nanostructures in shapes and configurations that weren’t possible before. This opens up new possibilities for wearable electronics, which are getting progressively smaller but are still bulkier than many people would like. If your FitBit is too clunky for your liking, there’s hope – technology like that documented in the KERI study could enable manufacturers to 3D print paper-thin, flexible devices that could be embedded in fabric, for example.
“We expect that the technique presented in this study will facilitate selection of diverse materials in 3D printing and enhance the freedom of integration for advanced conceptual devices,” the researchers state.
Authors of the study include Jung Hyun Kim, Sanghyeon Lee, Muhammad Wajahat, Hwakyung Jeong, Won Suk Chang, Hee Jin Jeong, Jong-Ryul Jang, Ji Tae Kim, and Seung Kwon Seol. Discuss in the Carbon Nanotubes forum at 3DPB.com.