Graphene has received a great deal of attention for its promising potential applications in electronics, biomedical and energy storage devices, sensors and other cutting-edge technological fields, mainly because of its fascinating properties such as an extremely high electron mobility, a good thermal conductivity and a high elasticity.
The successful implementation of graphene-based devices invariably requires the precise patterning of graphene sheets at both the micrometer and nanometer scale. Finding the ideal technique to achieve the desired graphene patterning remains a major challenge.
3D printing, also known as additive manufacturing, is becoming a viable alternative to conventional manufacturing processes in an increasing number of applications ranging from children toys to cars, fashion, architecture, military, biomedical science, and aerospace, to name a few.
For the first time, researchers have now demonstrated 3D printed nanostructures composed entirely of graphene using a new 3D printing technique. The research team, led by Professor Seung Kwon Seol from Korea Electrotechnology Research Institute (KERI), has published their findings in the November 13, 2014 online edition of Advanced Materials ("3D Printing of Reduced Graphene Oxide Nanowires")
"We developed a nanoscale 3D printing approach that exploits a size-controllable liquid meniscus to fabricate 3D reduced graphene oxide (rGO) nanowires," Seol explains. "Different from typical 3D printing approaches which use filaments or powders as printing materials, our method uses the stretched liquid meniscus of ink. This enables us to realize finer printed structures than a nozzle aperture, resulting in the manufacturing of nanotructures."
Using this technique, they were able to produce arrays of different freestanding rGO architectures, grown directly at chosen sites and in different directions: straight wires, bridges, suspended junctions, and woven structures.
"So far, to the best of our knowledge, nobody has reported 3D printed nanostructures composed entirely of graphene," says Seol. "Several results reported the 3D printing (millimeter- or centimeter-scale) of graphene or carbon nanotube/plastic composite materials by using a conventional 3D printer. In such composite system, the graphene (or CNT) plays an important role for improving the properties of plastic materials currently used in 3D printers. However, the plastic materials used for producing the composite structures deteriorate the intrinsic properties of graphene (or CNT)."
He points out that this 3D nanoprinting approach can be used for manufacturing 2D patterns and 3D architectures in diverse devices such as printed circuit boards, transistors, light emitting devices, solar cells, sensors and so on. Reducing the 3D printable size to below 10 nm and increasing the production yield still remain challenges, though.
Source: Nanowerk