Some of you may be tired of me writing at great lengths about the extraordinary properties exhibited by the recently discovered material, graphene. One of the most conductive materials known to man, with strength-to-weight ratios unheard of until recently, the material could play a major role in virtually every industry out there in some form or another.
If you think that I already sound pretty excited, then wait until you hear me talk about the 3D printing of graphene! It’s already been done to some extent. Companies such as Graphene 3D Lab, in which I’ve had the pleasure of meeting their CEO, Daniel Stolyarov last month in California, are at the forefront of this area. With that said, there is a difference between 3D printing pure graphene, and 3D printing a graphene/thermoplastic composites like Graphene 3D has been doing.
While printing with composite materials, using a typical FDM/FFF or powder based laser sintering process, will keep some of graphene’s superior properties intact, most will be lost. The plastic will eventually break down leaving any prints weak, and not much different from a typical object you’d print with a MakerBot Replicator using PLA or ABS filament. Some conductive properties of the graphene will shine through though, but they too will be limited.
Researchers, led by Professor Seung Kwon Seol from Korea Electrotechnology Research Institute (KERI), recently published a paper in Advanced Materials called ‘3D Printing of Reduced Graphene Oxide Nanowires‘. In the paper they describe a groundbreaking new process of directly 3D printing pure graphene. This means that 100% graphene nano-structures can be fabricated without the use of any other material. Since the entire printed structure is composed of graphene, the strength, as well as full conductivity of the material is able to be realized.
“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).”
Basically, the researchers rely on a meniscus, which is the curve in the upper surface of a liquid close to the surface, which is created inside of a very tiny chemical dropper known as a micropipette. The micropipette is filled with a colloidal dispersion of graphene oxide sheets which are reduced via evaporation by treating it with a chemical (hydrazine) and a rise in temperature. They then need to extrude the graphene oxide from the micropipette which is done simply by pulling the pipette slowly away from the surface as the evaporation takes place. The results were remarkable, free standing graphene oxide which they were able to produce in various arrays of architectures, including bridges, suspended junctions, woven structures and more.
Researchers have also shown that it’s entirely possible to use this technique to 3D print nanostructures out of many different materials as well. Although there is still work to be done, particularly in increasing the process’ production yields, as well as reducing the size of the extruded material to under 10nm, such techniques should further progress within the production of solar cells, sensors, circuit boards, transistors, LEDs an many other items.
Let’s hear your thoughts on this new approach to graphene printing in the 3D Printed Nano Graphene Structure forum thread on 3DPB.com. Check out the video of the process below: